Biology subjects

Taylor, L.

Publications and source records attributed to Taylor, L..

At least 37 records · Page 2Linked to original sources

bioRxiv2024

A male-essential microRNA is key for avian sex chromosome dosage compensation

Birds have a sex chromosome system in which females are heterogametic (ZW) and males are homogametic (ZZ). The differentiation of avian sex chromosomes from ancestral autosomes entailed the loss of most genes from the W chromosome during evolution. However, to what extent mechanisms evolved that counterbalance the consequences of this extensive gene dosage reduction in female birds has remained unclear. Here we report functional in vivo and evolutionary analyses of a Z-chromosome-linked microRNA (miR-2954) with strongly male-biased expression that was previously proposed to play a key role in sex chromosome dosage compensation1. We knocked out miR-2954 in chicken, which resulted in early embryonic lethality of homozygous knockout males, likely due to the highly specific upregulation of dosage-sensitive Z-linked target genes of miR-2954. Our evolutionary gene expression analyses further revealed that these dosage-sensitive target genes have become upregulated on the single Z in female birds during evolution. Altogether, our work unveils a scenario where evolutionary pressures on females following W gene loss led to the evolution of transcriptional upregulation of dosage-sensitive genes on the Z not only in female but also in male birds. The resulting overabundance of transcripts in males resulting from the combined activity of two dosage-sensitive Z gene copies was in turn offset by the emergence of a highly targeted miR-2954-mediated transcript degradation mechanism during avian evolution. Our findings demonstrate that birds have evolved a unique sex chromosome dosage compensation system in which a microRNA has become essential for male survival.

evolutionary biology↗

bioRxiv2024

Cerebrovascular pathology mediates associations between hypoxemia during rapid eye movement sleep and medial temporal lobe structure and function in older adults

Obstructive sleep apnea (OSA) is common in older adults and is associated with medial temporal lobe (MTL) degeneration and memory decline in aging and Alzheimers disease (AD). However, the underlying mechanisms linking OSA to MTL degeneration and impaired memory remains unclear. By combining magnetic resonance imaging (MRI) assessments of cerebrovascular pathology and MTL structure with clinical polysomnography and assessment of overnight emotional memory retention in older adults at risk for AD, cerebrovascular pathology in fronto-parietal brain regions was shown to statistically mediate the relationship between OSA-related hypoxemia, particularly during rapid eye movement (REM) sleep, and entorhinal cortical thickness. Reduced entorhinal cortical thickness was, in turn, associated with impaired overnight retention in mnemonic discrimination ability across emotional valences for high similarity lures. These findings identify cerebrovascular pathology as a contributing mechanism linking hypoxemia to MTL degeneration and impaired sleep-dependent memory in older adults.

neuroscience↗

bioRxiv2023

Adenosine Kinase regulates Sleep Timing and the Homeostatic Sleep Response through Distinct Molecular Pathways

Sleep behaviour is broadly regulated by two drives, the circadian (Process C), which is orchestrated by the suprachiasmatic nuclei (SCN), and controls sleep timing, and the homeostatic (Process S), which controls sleep amount and the response to sleep deprivation (Borbely et al., 2016). However, the molecular pathways that mediate their independent effects, and their interactions remain unclear. Adenosine is an important integrator of both processes (Bjorness & Greene, 2009; Jagannath et al., 2021, 2022), such that adenosine levels track and modulate wakefulness, whilst adenosine signalling inhibits the circadian response to light. Therefore, we studied the sleep/circadian behaviour, and cortical and SCN transcriptomic profiles of a mouse model overexpressing Adenosine Kinase (Adk-Tg) (Fedele et al., 2005), (Palchykova et al., 2010). We found that overall, the Adk-Tg mouse slept less and showed lower amplitude circadian rhythms with an altered sleep/wake distribution across the 24h day, which correlated with changes in transcription of synaptic signalling genes that would shift the excitatory/inhibitory balance. In addition, the Adk-Tg mouse showed a reduced level of ERK phosphorylation, and attenuation of DNA repair related pathways. After sleep deprivation, however, the Adk-Tg mouse significantly increased relative to wildtype, immediate early gene expression levels including of Arc, but paradoxically reduced ERK phosphorylation. Thus, baseline sleep levels and timing are regulated by ERK signalling, whereas the response to sleep loss is mediated by the alteration of the transcriptomic landscape independently of ERK.

molecular biology↗

bioRxiv2023

Sex specific regulation of the cortical transcriptome in response to sleep deprivation

Multiple studies have documented sex differences in sleep behaviour, however the molecular determinants of such differences remain unknown. Furthermore, most studies addressing molecular mechanisms have been performed only in males, leaving the current state of knowledge biased towards the male sex. To address this, we studied the differences in the transcriptome of the cerebral cortex of male and female C57Bl/6J mice after six hours of sleep deprivation. We found that several genes, including the neurotrophin growth factor Bdnf, immediate early genes Fosb and Fosl2, and the adenylate cyclase Adcy7 are differentially upregulated in males compared to females. We identified the androgen-receptor activating transcription factor EZH2 as the upstream regulatory element specifying sex differences in the sleep deprivation transcriptome. We propose that the pathways downstream of these transcripts, which impact on cellular re-organisation, synaptic signalling and learning may underpin the differential response to sleep deprivation in the two sexes.

molecular biology↗

bioRxiv2023

SARS-CoV-2 ORF8 modulates lung inflammation and clinical disease progression

The virus severe acute respiratory syndrome coronavirus 2, SARS-CoV-2, is the causative agent of the current COVID-19 pandemic. It possesses a large 30 kilobase (kb) genome that encodes structural, non-structural, and accessory proteins. Although not necessary to cause disease, these accessory proteins are known to influence viral replication and pathogenesis. Through the synthesis of novel infectious clones of SARS-CoV-2 that lack one or more of the accessory proteins of the virus, we have found that one of these accessory proteins, ORF8, is critical for the modulation of the host inflammatory response. Mice infected with a SARS-CoV-2 virus lacking ORF8 exhibit increased weight loss and exacerbated macrophage infiltration into the lungs. Additionally, infection of mice with recombinant SARS-CoV-2 viruses encoding ORF8 mutations found in variants of concern reveal that naturally occurring mutations in this protein influence disease severity. Our studies with a virus lacking this ORF8 protein and viruses possessing naturally occurring point mutations in this protein demonstrate that this protein impacts pathogenesis. SignificanceSince its emergence in 2019, SARS-CoV-2 has accrued mutations throughout its 30kb genome. Of particular interest are the mutations present in the ORF8 protein, which occur in every major variant. The precise function and impact of this protein on disease severity and pathogenesis remains understudies. Our studies reveal that the ORF8 protein modulates the immune response by impacting macrophage infiltration into the lungs. Additionally, we have shown that the ORF8 protein of SARS-CoV-2 has accrued mutations throughout its evolution that lead to a loss of function phenotype in this protein. Our work reveals that the ORF8 protein of SARS-CoV-2 contributes significantly to disease progression through modulation of the inflammatory response.

microbiology↗

bioRxiv2023

CD4+ T cell-derived IL21 regulates stem cell fate in acute myeloid leukemia by activation of p38-MAPK signaling

Self-renewal programs in leukemia stem cells (LSCs) predict poor prognosis in acute myeloid leukemia (AML) patients. We identified CD4+ T cell-derived interleukin (IL) 21 as an important negative regulator of self-renewal of murine and human LSCs, but not hematopoietic stem cells. IL21/IL21R signaling favored asymmetric cell division and differentiation in LSCs through accumulation of reactive oxygen species (ROS) and activation of p38-MAPK signaling, resulting in reduced LSCs number and significantly prolonged survival in murine AML models. In human AML, serum IL21 at diagnosis was identified as an independent positive prognostic biomarker for outcome and correlated with better survival and higher complete remission rate in patients that underwent high-dose chemotherapy. IL21 inhibited primary AML LSCs function in vitro by activating ROS and p38-MAPK signaling and this effect was enhanced by cytarabine treatment. Consequently, promoting IL21/IL21R signaling on LSCs may be a novel approach to decrease stemness and increase differentiation in AML.

cancer biology↗

bioRxiv2023

A framework for linking hemispheric, full annual cycle prioritizations to local conservation actions for migratory birds

The conservation of migratory birds poses a fundamental challenge: their conservation requires coordinated action across the hemisphere, but those actions must be designed and implemented locally. To address this challenge, we describe a multi-level framework for linking broad-scale, full annual cycle prioritizations to local conservation actions for migratory birds. We developed hemisphere-scale spatial prioritizations for the full annual cycle of migratory birds that breed in six different ecosystems in North America. The full annual cycle prioritizations provide a hemispheric context within which regional priorities can be identifieed. Finer resolution, regional prioritizations can then inform local conservation actions more effectively. We describe the importance of local conservation practitioner contributions at each level of the process and provide two examples of regional spatial prioritizations that were developed to guide local action. The fierst example focused on coastal North and South Carolina, USA, and used information on marsh birds, shorebirds, ecological integrity, and co-benefiets for people to identify Cape Romain, South Carolina as a high-priority site for conservation action. The second example in Colombia used information on migrant and resident birds to identify the Cauca Valley as a high priority site. The multi-level conceptual framework we describe is one pathway for identifying sites for implementation of local conservation actions that are guided by conservation priorities for migratory birds across their full annual cycle.

ecology↗

bioRxiv2023

Periostin facilitates ovarian cancer recurrence by enhancing cancer stemness

Ovarian cancer (OC) is the deadliest reproductive system cancer. Its high lethality is due to the high recurrence rate and the development of chemotherapeutic resistance, which requires synergy between cancer cells and non-cancerous cells of the tumor microenvironment (TME). Analysis of gene expression microarray data from paired primary and recurrent OC tissues revealed significantly elevated expression of the gene encoding periostin (POSTN) in recurrent OC compared to matched primary tumors (p=0.014). Finding POSTN primarily localized to the TME, we investigated the role of TME POSTN in OC cell viability, migration/invasion, and chemosensitivity. Conditioned media with high levels of POSTN (CMPOSTNhigh) was generated using POSTN-transfected fibroblastic preadipocyte 3T3-L1 cells. CMPOSTNhigh-cultured OC cells exhibited faster migration, more invasiveness (p=0.006), and more chemoresistance (p<0.05) compared to OC cells cultured with control medium (CMCTL). Furthermore, CMPOSTNhigh-cultured HEYA8 cells demonstrated increased resistance to paxlitaxel-induced apoptosis. Multiple OC cell lines (HEYA8, CAOV2, and SKOV3) cultured with CMPOSTNhighshowed increases in stem cell side population relative to CMCTL-cultured cells. POSTN-transfected 3T3-L1 cells exhibited more intracellular and extracellular lipids, and this was linked to increased cancer cell expression of the oncogene fatty acid synthetase (FASN). Additionally, POSTN functions in the TME were linked to Akt pathway activities. In a xenograft mouse model of OC, the mean tumor volume in mice injected with CMPOSTNhigh-grown OC cells was larger than that in mice injected with CMCTL-grown OC cells (p=0.0023). Altogether, higher POSTN expression is present in recurrent OC and promotes a more aggressive and chemoresistant oncogenic phenotype in vitro. Within cancer TME fibroblasts, POSTN can stimulate lipid production and is associated with increased OC stem cell side population, consistent with its known role in maintaining stemness. Our results bolster the need for further study of POSTN as a potential therapeutic target in treatment and potential prevention of recurrent ovarian cancer. Author SummaryOvarian cancer has a high rate of recurrent disease that is often resistant to chemotherapy. Comparing primary and recurrent ovarian cancer tumors, we found that the gene POSTN, which encodes the protein periostin, is more highly expressed in recurrent tumors, and more highly expressed in the tumor microenvironment, outside of the cancer cells. We transfected cells with vectors encoding POSTN or with blank vectors to generate conditioned media with high POSTN or control media. Ovarian cancer cells cultured in the POSTN-high conditioned media showed faster wound healing, more invasiveness, and more resistance to apoptosis caused by chemotherapeutic agents, and increased stemness, an important trait in cancer cells, especially recurrent cells. POSTN-transfected cells showed higher expression of the enzyme fatty acid synthase and higher concentrations of lipids, indicating that POSTN may play a role in increasing the energy available to cancer cells. The Akt pathway, often activated in ovarian cancer growth, was activated more in cells cultured in the POSTN-high environment. Finally, we injected immunocompromised mice with ovarian cancer cells that were grown in either the POSTN-high media or the control media, and the average tumor size was higher in mice injected with the cells that were grown in the POSTN-high media.

cancer biology↗

bioRxiv2023

Where, who, and what counts under area-based conservation targets: A framework for identifying opportunities that benefit biodiversity, climate mitigation, and human communities

O_LIArea-based conservation targets, such as 30-30, if strategically applied, can increase resiliency to climate change and provide co-benefits to people and biodiversity. However, protected areas historically were not designated within the context of global change, and human communities at highest risk are often overlooked in conservation planning. C_LIO_LITo inform 30-30 conservation planning in the United States (i.e., America the Beautiful; ATB), we evaluated where US conservation opportunities exist by identifying habitats that can simultaneously benefit climate change mitigation and bird populations, as well as who lives in these areas and how conservation actions could both improve human well-being or potentially be at odds with local communities. To inform the equitable implementation of area-based conservation targets, we integrated maps of critical habitat for birds now and under a changing climate with carbon stocks and sinks and developed a prioritization framework to investigate the spatial alignment of these locations with areas identified as important for both human well-being and land-dependent human communities. C_LIO_LIAlthough nearly 30% of US lands have some level of protection, only 6% of US lands (143 million acres) are managed for biodiversity and align with Bird and Carbon (BC) priorities, and <3% of protected US lands (59 million acres) align with priorities for Birds, Carbon, and Human well-being (BCH). C_LIO_LIOf the 312 million acres of BCH priorities identified, 71% lack known protection or formal conservation plans (14% of US lands) and should be considered conservation opportunities that could simultaneously address the biodiversity and climate crises, and social inequities. Targeting these BCH areas for conservation action would contribute to more equitable benefits to marginalized communities, and could fulfill the Justice 40 commitment, which aims to allocate 40% of federal investments in climate benefits to marginalized communities (which, for the 30% goal under ATB equates to 12% of US lands). C_LIO_LIAt least 80% of all BCH priorities co-occur with Indigenous peoples and local communities (IPLCs) who have strong cultural and socioeconomic ties to the land, making it imperative to work with local communities to define what counts as conservation actions towards the 30% goal and what successful conservation outcomes that benefit biodiversity, climate change mitigation, and human communities look like. C_LI

ecology↗

bioRxiv2022

Loss of allosteric regulation in α-isopropylmalate synthase identified as an antimicrobial resistance mechanism

Despite our best efforts to discover new antimicrobials, bacteria have evolved mechanisms to become resistant. Resistance to antimicrobials can be attributed to innate, inducible, and acquired mechanisms. Mycobacterium abscessus is one of the most antimicrobial resistant bacteria and is known to cause chronic pulmonary infections within the cystic fibrosis community. Previously, we identified epetraborole as an inhibitor against M. abscessus with in vitro and in vivo activities and that the efficacy of epetraborole could be improved with the combination of the non-proteinogenic amino acid norvaline. Norvaline demonstrated activity against the M. abscessus epetraborole resistant mutants thus, limiting resistance to epetraborole in wild type populations. Here we show M. abscessus mutants with resistance to epetraborole can acquire resistance to norvaline in a leucyl-tRNA synthetase (LeuRS) editing-independent manner. After showing that the membrane hydrophobicity and efflux activity are not linked to norvaline resistance, whole-genome sequencing identified a mutation in the allosteric regulatory domain of -isopropylmalate synthase (-IPMS). We found that mutants with the -IPMSA555V variant incorporated less norvaline in the proteome and produced more leucine than the parental strain. Furthermore, we found that leucine can rescue growth inhibition from norvaline challenge in the parental strain. Our results demonstrate that M. abscessus can modulate its metabolism through mutations in an allosteric regulatory site to upregulate the biosynthesis of the natural LeuRS substrate and outcompete norvaline. These findings emphasize the antimicrobial resistant nature of M. abscessus and describe a unique mechanism of substrate-inhibitor competition. Significance StatementCystic fibrosis patients and individuals undergoing plastic surgery are at risk for acquiring chronic infections from Mycobacterium abscessus. Current antibiotics are not adequate and require increased drug discovery efforts to identify better treatments for these patients. The benzoxaborole, epetraborole has been shown by our group and others to be a promising candidate against M. abscessus but the emergence of resistance to epetraborole in a clinical trial for complicated urinary tract infections has hindered its development. Previously, we identified the combination of epetraborole and norvaline as a potential means to limit resistance against epetraborole. Our results here demonstrate that M. abscessus can acquire resistance to both epetraborole and norvaline. These results may help develop combination therapies to reduce the risk of resistance to benzoxaboroles and non-proteinogenic amino acids.

microbiology↗

bioRxiv2022

SARS-CoV-2 Variant Spike and accessory gene mutations alter pathogenesis

The ongoing COVID-19 pandemic is a major public health crisis. Despite the development and deployment of vaccines against SARS-CoV-2, the pandemic persists. The continued spread of the virus is largely driven by the emergence of viral variants, which can evade the current vaccines through mutations in the Spike protein. Although these differences in Spike are important in terms of transmission and vaccine responses, these variants possess mutations in the other parts of their genome which may affect pathogenesis. Of particular interest to us are the mutations present in the accessory genes, which have been shown to contribute to pathogenesis in the host through innate immune signaling, among other effects on host machinery. To examine the effects of accessory protein mutations and other non-spike mutations on SARS-CoV-2 pathogenesis, we synthesized viruses where the WA1 Spike is replaced by each variant spike genes in a SARS-CoV-2/WA-1 infectious clone. We then characterized the in vitro and in vivo replication of these viruses and compared them to the full variant viruses. Our work has revealed that non-spike mutations in variants can contribute to replication of SARS-CoV-2 and pathogenesis in the host and can lead to attenuating phenotypes in circulating variants of concern. This work suggests that while Spike mutations may enhance receptor binding and entry into cells, mutations in accessory proteins may lead to less clinical disease, extended time toward knowing an infection exists in a person and thus increased time for transmission to occur. SignificanceA hallmark of the COVID19 pandemic has been the emergence of SARS-CoV-2 variants that have increased transmission and immune evasion. Each variant has a set of mutations that can be tracked by sequencing but little is known about their affect on pathogenesis. In this work we first identify accessory genes that are responsible for pathogenesis in vivo as well as identify the role of variant spike genes on replication and disease in mice. Isolating the role of Spike mutations in variants identifies the non-Spike mutations as key drivers of disease for each variant leading to the hypothesis that viral fitness depends on balancing increased Spike binding and immuno-evasion with attenuating phenotypes in other genes in the SARS-CoV-2 genome.

microbiology↗

bioRxiv2022

Entorhinal-hippocampal circuit integrity is related to mnemonic discrimination and amyloid-β pathology in older adults

Mnemonic discrimination, a cognitive process that relies on hippocampal pattern separation, is one of the first memory domains to decline in aging and preclinical Alzheimers disease. We tested if functional connectivity (FC) within the entorhinal-hippocampal circuit, measured with high-resolution resting state fMRI, is associated with mnemonic discrimination and A{beta} pathology, measured with PET, in nondemented older adults. Low object mnemonic discrimination performance was specifically associated with increased FC between anterolateral entorhinal cortex (alEC) and dentate gyrus (DG)/CA3, supporting the importance of this connection to object memory. This hyperconnectivity between alEC-DG/CA3 was related to A{beta} pathology and decreased entorhinal cortex volume. In contrast, spatial mnemonic discrimination was not associated with altered FC. A{beta} was further associated with decreased FC and volume within hippocampal subfields. Our findings suggest that A{beta} may indirectly lead to memory impairment through entorhinal-hippocampal circuit dysfunction and neurodegeneration, and provide a mechanism for vulnerability of object mnemonic discrimination.

neuroscience↗

bioRxiv2022

Landscape change and alien invasions drive shifts in native lady beetle communities over a century

AimUnderstanding drivers of insect population declines is essential for the development of successful conservation plans, but data limitations restrict assessment across spatial and temporal scales. Museum records represent a unique source of historical data that can be leveraged to investigate temporal trends in insect communities. Native lady beetle decline has been attributed to competition with established alien species and landscape change, but the relative importance of these drivers is difficult to measure with short-term field-based studies. Here we assessed distribution patterns for native lady beetle species over 12 decades using museum records and evaluated the relative importance of alien species and landscape change as long-term drivers contributing to changes in lady beetle communities. LocationOhio, USA. MethodsWe compiled occurrence records for 28 lady beetle species collected in Ohio, USA from 1900-2018. Incidence-based measures of taxonomic beta-diversity were used to evaluate changes in lady beetle community composition over time. To evaluate the relative influence of temporal, spatial, landscape, and community drivers on the captures of native lady beetles, we constructed negative binomial generalized additive models. ResultsWe report evidence of declines in captures for several native species, including Adalia bipunctata, Coccinella novemnotata, Hippodamia convergens, and Coleomegilla maculata. Importantly, the timing, severity, and drivers of these documented declines were species-specific. Changes in lady beetle species composition began in the 1980s, when processes of species loss/gain and turnover shifted communities towards dominance by a few alien lady beetle species. Land cover change also was associated with declines in captures, particularly for C. novemnotata which declined prior to the arrival of alien species in the state. Main conclusionsOur study documented shifts in Ohios lady beetle communities beginning in the 1980s as alien species supplanted natives. Drivers of declines in captures of native lady beetle species were highly species-specific, emphasizing that mechanisms driving population losses cannot be generalized even among closely related species. These findings also indicate the importance of museum holdings and the analysis of species-level data when studying temporal trends in insect populations.

ecology↗

bioRxiv2022

Sleep and circadian rhythm disruption alters the lung transcriptome to predispose to viral infection

Sleep and circadian rhythm disruption (SCRD), as encountered during shift work, increases the risk of respiratory viral infection including SARS-CoV-2. However, the mechanism(s) underpinning higher rates of respiratory viral infection following SCRD remain poorly characterised. To address this, we investigated the effects of acute sleep deprivation on the mouse lung transcriptome. Here we show that sleep deprivation profoundly alters the transcriptional landscape of the lung, causing the suppression of both innate and adaptive immune systems, disrupting the circadian clock, and activating genes implicated in SARS-CoV-2 replication, thereby generating a lung environment that promotes viral infection and associated disease pathogenesis. Our study provides a mechanistic explanation of how SCRD increases the risk of respiratory viral infections including SARS-CoV-2 and highlights therapeutic avenues for the prevention and treatment of COVID-19.

neuroscience↗

bioRxiv2021

Somnotate: A robust automated sleep stage classifier that exceeds human performance and identifies ambiguous states in mice

Electrophysiological recordings from freely behaving animals are a widespread and powerful mode of investigation in sleep research. These recordings generate large amounts of data that require sleep stage annotation (polysomnography), in which the data is parcellated according to three vigilance states: awake, rapid eye movement (REM) sleep, and non-REM (NREM) sleep. Manual and computational annotation methods currently ignore intermediate states because the classification features become ambiguous. However, these intermediate states contain important information regarding vigilance state dynamics. Here, we present a new classifier, "Somnotate", which produces automated annotation accuracies that exceed human expert performance on mouse electrophysiological data, is robust to errors in the training data, compatible with different recording configurations, and maintains high performance during experimental interventions. Somnotate is a probabilistic classifier based on a combination of linear discriminant analysis (LDA) with a hidden Markov model (HMM). A unique feature of Somnotate is that it quantifies and reports the certainty of its annotations, enabling the experimenter to identify ambiguous recording periods in a principled manner. We leverage this feature to identify epochs that exhibit intermediate vigilance states, revealing that many of these cluster around state transitions, whereas others correspond to failed attempts to transition. We show that the success rates of different transitions can be experimentally manipulated and explain previously observed sleep patterns. Somnotate can thus facilitate the study of sleep stage transitions and offers new insight into the mechanisms underlying sleep-wake dynamics. Author summaryTypically, the three different vigilance states - awake, REM sleep, and non-REM sleep - exhibit distinct features that are readily recognised in electrophysiological recordings. However, particularly around vigilance state transitions, epochs often exhibit features from more than one state. These intermediate vigilance states pose challenges for existing manual and automated classification methods, and are hence often ignored. Here, we present Somnotate - an open-source, highly accurate and robust sleep stage classifier, which supports research into intermediate states and sleep stage dynamics. Somnotate quantifies and reports the certainty of its annotations, enabling the experimenter to identify abnormal epochs in a principled manner. We use this feature to identify intermediate states and to detect unsuccessful attempts to switch between vigilance states. This provides new insights into the mechanisms of vigilance state transitions in mice, and creates new opportunities for future experiments.

neuroscience↗

bioRxiv2021

Direct cryopreservation of poultry/avian embryonic reproductive cells: A low-tech, cost-effective and efficient method for safeguarding genetic diversity

Chickens are an important resource for smallholder farmers who raise locally adapted, genetically distinct breeds for eggs and meat. The development of efficient reproductive technologies to conserve and regenerate chicken breeds safeguards existing biodiversity and secures poultry genetic resources for climate resilience, biosecurity, and future food production. The majority of the over 1600 breeds of chicken are raised in low and lower to middle income countries (LMICs) under resource limited, small scale production systems, which necessitates a low tech, cost effective means of conserving diversity is needed. Here, we validate a simple biobanking technique using cryopreserved embryonic chicken gonads. The gonads are quickly isolated, visually sexed, pooled by sex, and cryopreserved. Subsequently, the stored material is thawed and dissociated before injection into sterile host chicken embryos. By using pooled GFP and RFP-labelled donor gonadal cells and Sire Dam Surrogate (SDS) mating, we demonstrate that chicks deriving entirely from male and female donor germ cells are hatched. This technology will enable ongoing efforts to conserve chicken genetic diversity for both commercial and small holder farmers, and to preserve existing genetic resources at poultry research facilities.

developmental biology↗

bioRxiv2021

Light-regulated SIK1 remodels the synaptic phosphoproteome to induce sleep

The sleep and circadian systems act in concert to regulate sleep-wake timing, yet the molecular mechanisms that underpin their interaction to induce sleep remain unknown. Synaptic protein phosphorylation, driven by the kinase SIK3, correlates with sleep pressure, however it is unclear whether these phosphoproteome changes are causally responsible for inducing sleep. Here we show that the light-dependent activity of SIK1 controls the phosphorylation of a subset of the brain phosphoproteome to induce sleep in a manner that is independent of sleep pressure. By uncoupling phosphorylation and sleep induction from sleep pressure, we establish that synaptic protein phosphorylation provides a causal mechanism for the induction of sleep under different environmental contexts. Furthermore, we propose a framework that details how the salt-inducible kinases regulate the synaptic phosphoproteome to integrate exogenous and endogenous stimuli, thereby providing the molecular basis upon which the sleep and circadian systems interact to control the sleep-wake cycle.

neuroscience↗

bioRxiv2021

Efficacy of epetraborole against Mycobacterium abscessus is increased with norvaline

Certain aminoacyl-tRNA synthetases developed a proofreading mechanism to ensure aminoacylation of tRNAs with cognate amino acids. Epetraborole (EPT) was identified as an inhibitor of the leucyl-tRNA synthetase (LeuRS) editing site in Mycobacterium abscessus. EPT displayed enhanced activity against M. abscessus over Mycobacterium tuberculosis. Crystallographic and equilibrium binding data showed that EPT binds LeuRSMabs and LeuRSMtb with similar Kd. Proteomic analysis revealed that when M. abscessus LeuRS mutants were fed the non-proteinogenic amino acid norvaline, leucine residues in proteins were replaced by norvaline, inducing expression of GroEL chaperonins and Clp proteases. In vitro data revealed that supplementation of media with norvaline reduced the emergence of EPT mutants in both M. abscessus and M. tuberculosis. The combination of EPT and norvaline had improved in vivo efficacy compared to EPT in a murine model of M. abscessus infection.

microbiology↗