Biology subjects

Zhao, L.

Publications and source records attributed to Zhao, L..

At least 235 records · Page 13Linked to original sources

bioRxiv2022

Tumor subclones, where are you?

IntroductionTumor clonal structure is closely related to future progression, which has been mainly investigated via mutation abundance clustering in bulk sample. With limited studies at single-cell resolution, a systematic comparison of the two approaches is still lacking. MethodsHere, using bulk and single-cell mutational data from liver and colorectal cancers, we would like to check the possibility of obtaining accurate tumor clonal structures from bulk-level analysis. We checked whether co-mutations determined by single-cell analysis had corresponding bulk variant allele frequency (VAF) peaks. We examined VAF ranges for different groups of co-mutations, and also the possibility of discriminating them. ResultsWhile bulk analysis suggested absence of subclonal peaks and possibly neutral evolution in some cases, single-cell analysis identified co-existing subclones. The overlaps of bulk VAF ranges for co-mutations from different subclones made it difficult to separate them, even with other parameter introduced. The difference between mutation cluster and tumor subclone is accountable for the challenge in bulk clonal deconvolution, especially in case of branched evolution as shown in colorectal cancer. ConclusionComplex subclonal structures and dynamic evolution are hidden under the seemingly clonal neutral pattern at bulk level, suggesting single-cell analysis will be needed to avoid under-estimation of tumor heterogeneity. Research HighlightsO_LIBulk-level mutation abundance clusters are not equal to tumor subclones. C_LIO_LIDifferent groups of co-mutations could not be discriminated at bulk-level. C_LIO_LISingle-cell mutational analysis can identify rather than infer tumor subclones. C_LIO_LICo-existing tumor subclones may have clonal neutral appearance at bulk-level. C_LI Lay summarySystematic comparison of tumor clonal structure differences between bulk and single-cell mutational analysis is lacking. Here we performed such as study and found that complex subclonal structures and dynamic evolution are hidden under clonal neutral appearance at bulk level in liver and colorectal cancers, suggesting single-cell analysis will be needed to avoid under-estimation of tumor heterogeneity.

cancer biology↗

bioRxiv2022

Structure of the histone acetyltransferase NuA4 complex

NuA4, one of two major histone acetyltransferase complexes in Saccharomyces cerevisiae, specifically acetylates histone H4 and H2A, and therefore loosen the histone-DNA contacts, resulting in increased transcriptional activity. Here we present a near-atomic resolution structure of NuA4 complex through cryonic electron microscopy. The structure comprises six subunits and a total of 5,000 amino acids, within which Eaf1 and Eaf2 twist against each other and span from Actin-Arp4 module to the platform subunit Tra1, forming the backbone of NuA4. The locations of four missing components including Yaf9, and Esa1, Yng2 and Eaf6 of Piccolo module were indicated based on the structure. Intriguingly, our biochemical data showed that NuA4 doesnt bind nucleosome in vitro, whereas possesses strong histone acetyltransferase activity. Its Piccolo module, which has long been regarded as the catalytic module of NuA4, acetylates the nucleosome substrate at almost the same efficiency, but is capable of binding nucleosome. Combining the structural and biochemical data give rise to a model in which the entire NuA4 adopts an auto-inhibited conformation, and undergoes structural rearrangements upon substrate and co-factor additions, restoring its capacity of nucleosome-binding and activity of hyper-acetylation.

biochemistry↗

bioRxiv2022

Cytoarchitectonic, receptor distribution and functional connectivity analyses of the macaque frontal lobe

Based on quantitative cyto- and receptor architectonic analyses, we identified 35 prefrontal areas and introduced a novel subdivision of Walkers areas 10, 9, 8B and 46. Statistical analysis of receptor densities revealed regional differences in lateral and ventrolateral prefrontal cortex. Since structural and functional organization of subdivisions encompassing areas 46 and 12 demonstrated significant differences in the interareal levels of 2 receptors. Furthermore, multivariate analysis included receptor fingerprints of previously identified 16 motor areas in the same macaque brains, and revealed five clusters encompassing frontal lobe areas. Based on the functional connectivity analysis, clustered areas showed similar connectivity distribution pattern. In particular, rostrally located areas (in clusters 1-2) were characterized by bigger fingerprints, i.e., higher receptor densities, and stronger regional interconnections. Whereas, more caudal areas (in clusters 3-5) had smaller fingerprints, but showed a widespread connectivity pattern with distant cortical regions. Taken together, present study provides a comprehensive insight into the molecular structure underlying the functional organization of the cortex and, thus, reconcile discrepancies between the structural and functional hierarchical organization of the primate frontal lobe. Finally, our data are publicly available via the EBRAINS and BALSA repositories for the entire scientific community.

neuroscience↗

bioRxiv2022

Pathobionts from chemically disrupted gut microbiota induce insulin-dependent diabetes in mice

BackgroundDysbiotic gut microbiome, genetically predisposed or chemically disrupted, has been linked with insulin-dependent diabetes (IDD) including autoimmune type 1 diabetes (T1D) in both humans and animal models. However, specific IDD-inducing gut bacteria remain to be identified and their casual role in disease development demonstrated via experiments that can fulfill Kochs postulates. ResultsHere, we show that novel gut pathobionts in the Muribaculaceae family, enriched by a low-dose dextran sulfate sodium (DSS) treatment, translocated to the pancreas and caused local inflammation, beta cell destruction and IDD in C57BL/6 mice. Antibiotic removal and transplantation of gut microbiota showed that this low DSS disrupted gut microbiota was both necessary and sufficient to induce IDD. Reduced butyrate content in the gut and decreased gene expression levels of an antimicrobial peptide in the pancreas allowed for the enrichment of members in the Muribaculaceae family in the gut and their translocation to the pancreas. Pure isolate of one such members induced IDD in wildtype germ-free mice on normal diet either alone or in combination with normal gut microbiome after gavaged into stomach and translocated to pancreas. ConclusionThe pathobionts that are chemically enriched in dysbiotic gut microbiota are sufficient to induce insulin-dependent diabetes after translocation to the pancreas. This indicates that IDD can be mainly a microbiome-dependent disease, inspiring the need to search for novel pathobionts for IDD development in humans.

microbiology↗

bioRxiv2022

Saturated cell lysing is critical for high sensitivity microbiome analysis

Introductory paragraphFor robust DNA-based gut microbiome analysis, all cells in the stool samples need to be lysed. However, no standards have been developed to evaluate a DNA extraction protocols capability of lysing all cells and its sensitivity on detecting microbial structural differences among samples. In this study, we incrementally increased the intensity of mechanical lysis and integrated lysozyme pretreatment to Protocol Q (PQ), which was recommended as the best from 21 protocols1. A new protocol (LPQ) was optimized when DNA yield, Gram-positive bacteria ratio, and beta diversity all reached to a plateau with no further significant changes, indicating the achievement of saturated lysing. LPQ detected significant differences among three groups of fiber-treated human stool samples and identified 64 responsive ASVs, while a commercial kit failed to detect any significant treatment effects and PQ only detected 17 responsive ASVs. Therefore, saturated lysing as defined in this study should be adopted for evaluating microbiome DNA extraction protocols.

microbiology↗

bioRxiv2022

The radio-protective effects of (-)-Epigallocatechin-3-gallate (EGCG): regulating macrophage function in radiation-induced intestinal injury.

Accidental and medical radiation exposure may cause radiation-induced intestinal injury (RIII), a catastrophic disease requiring efficient therapies. (-)-Epigallocatechin-3-gallate (EGCG), a major constituent of green tea, has been shown to have potent biological activity as well as strong anti-inflammation effects. Here, we demonstrate that EGCG treatment not only protects mice against total body irradiation (TBI)-induced toxicity and weight loss but also alleviates whole abdominal irradiation (WAI)-induced intestinal injury. EGCG promotes proliferation and survival of intestinal stem cells, inhibits radiation-induced apoptosis and inflammation. At the same time, EGCG preserves the composition of the gut microbiota in WAI mice. In vitro, we demonstrate that EGCG regulates the release of radiation-induced inflammatory factors by inhibiting inflammatory pathways such as toll-like receptor signaling pathway in peritoneal macrophages. Mechanistically, the radioprotective effect of EGCG was likely attributable to its preservation on macrophages and the colonized gut microbiota composition, thus relieving the intestinal inflammation. EGCG provides a novel strategy to mitigate RIII and improve the prognosis of patients after radiotherapy.

cell biology↗

bioRxiv2022

BA.2.12.1, BA.4 and BA.5 escape antibodies elicited by Omicron infection

SARS-CoV-2 Omicron sublineages BA.2.12.1, BA.4 and BA.5 exhibit higher transmissibility over BA.21. The new variants receptor binding and immune evasion capability require immediate investigation. Here, coupled with Spike structural comparisons, we show that BA.2.12.1 and BA.4/BA.5 exhibit comparable ACE2-binding affinities to BA.2. Importantly, BA.2.12.1 and BA.4/BA.5 display stronger neutralization evasion than BA.2 against the plasma from 3-dose vaccination and, most strikingly, from post-vaccination BA.1 infections. To delineate the underlying antibody evasion mechanism, we determined the escaping mutation profiles2, epitope distribution3 and Omicron neutralization efficacy of 1640 RBD-directed neutralizing antibodies (NAbs), including 614 isolated from BA.1 convalescents. Interestingly, post-vaccination BA.1 infection mainly recalls wildtype-induced humoral memory. The resulting elicited antibodies could neutralize both wildtype and BA.1 and are enriched on non-ACE2-competing epitopes. However, most of these cross-reactive NAbs are heavily escaped by L452Q, L452R and F486V. BA.1 infection can also induce new clones of BA.1-specific antibodies that potently neutralize BA.1; nevertheless, these NAbs are largely escaped by BA.2/BA.4/BA.5 due to D405N and F486V, and react weakly to pre-Omicron variants, exhibiting poor neutralization breadths. As for therapeutic NAbs, Bebtelovimab4 and Cilgavimab5 can effectively neutralize BA.2.12.1 and BA.4/BA.5, while the S371F, D405N and R408S mutations would undermine most broad sarbecovirus NAbs. Together, our results indicate that Omicron may evolve mutations to evade the humoral immunity elicited by BA.1 infection, suggesting that BA.1-derived vaccine boosters may not achieve broad-spectrum protection against new Omicron variants.

immunology↗

bioRxiv2022

Two Competing Guilds as a Core Microbiome Signature for Chronic Diseases

Summary ParagraphOver eons of co-evolution, the gut microbiota has become an essential organ for humans1,2. However, it is unclear what core members and their ecological organization ensures the stable provision of this organs essential health-relevant functions to the host. With high quality metagenome-assembled genomes as network nodes, here we identified two competing guilds3 of the most stably and highly connected bacteria that together correlate with a wide range of host health conditions. Genomes in these two guilds kept their ecological relationship unchanged despite experiencing profound abundance changes during a 3-month high fiber intervention and 1-year follow-up in patients with type 2 diabetes (T2DM). The genomes of one guild harbored more genes for plant polysaccharide degradation and butyrate production, while the other guild had more genes for virulence or antibiotic resistance. A Random Forest regression model showed that the abundance distributions of these genomes were associated with 41 out of 43 bio-clinical parameters in the study cohort. With these genomes as reference, Random Forest modeling successfully classified case and control of T2DM, atherosclerotic cardiovascular disease, liver cirrhosis, inflammatory bowel diseases, colorectal cancer, ankylosing spondylitis, schizophrenia, and Parkinsons disease in 12 independent metagenomic datasets from 1,816 participants across ethnicity and geography. This core microbiome signature may serve as a common target for health recovery.

microbiology↗

bioRxiv2022

Niclosamide targets macrophages to rescue the disrupted peritoneal homeostasis in endometriosis

Due to the vital roles of macrophages in the pathogenesis of endometriosis, targeting macrophages could be a new therapeutic direction. Here, we investigated the efficacy of niclosamide for the resolution of perturbed microenvironment caused by dysregulated macrophages in a mouse model of endometriosis. Single-cell transcriptomic analysis revealed the heterogeneity of macrophage subpopulations including three newly identified intermediate subtypes with sharing characteristics of traditional "small" or "large" peritoneal macrophages (SPMs and LPMs) in the peritoneal cavity. Endometriosis-like lesions (ELL) enhanced the differentiation of recruited macrophages, promoted the replenishment of resident LPMs, and increased ablation of embryo-derived LPMs, which were stepwise suppressed by niclosamide. In addition, niclosamide reversed intercellular communications between macrophages and B cells which were disrupted by ELL. Therefore, niclosamide rescued the perturbed microenvironment in endometriosis through its fine regulations on the dynamic progression of macrophages and could be a new promising therapy for endometriosis. SummaryNiclosamide tunes the dynamic progression of peritoneal macrophages and their intercellular communications with B cells to rescue the disrupted microenvironment in the peritoneal cavity in a mouse model of endometriosis. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=155 SRC="FIGDIR/small/487220v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@e6700eorg.highwire.dtl.DTLVardef@c6c557org.highwire.dtl.DTLVardef@1c60b92org.highwire.dtl.DTLVardef@121bce6_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphic AbstractC_FLOATNO C_FIG

molecular biology↗

bioRxiv2022

Systematic identification of unannotated ORFs in Drosophila reveals evolutionary heterogeneity

De novo gene origination, where a previously non-genic genomic sequence becomes genic through evolution, has been increasingly recognized as an important source of evolutionary novelty across diverse taxa. Many de novo genes have been proposed to be protein-coding, and in several cases have been experimentally shown to yield protein products. However, the systematic study of de novo proteins has been hampered by doubts regarding the translation of their transcripts without the experimental observation of protein products. Using a systematic, ORF-focused mass-spectrometry-first computational approach, we identify almost 1000 unannotated open reading frames with evidence of translation (utORFs) in the model organism Drosophila melanogaster, 371 of which have canonical start codons. To quantify the comparative genomic similarity of these utORFs across Drosophila and to infer phylostratigraphic age, we further develop a synteny-based protein similarity approach. Combining these results with reference datasets on tissue- and life-stage-specific transcription and conservation, we identify different properties amongst these utORFs. Contrary to expectations, the fastest-evolving utORFs are not the youngest evolutionarily. We observed more utORFs in the brain than in the testis. Most of the identified utORFs may be of de novo origin, even accounting for the possibility of false-negative similarity detection. Finally, sequence divergence after an inferred de novo origin event remains substantial, raising the possibility that de novo proteins turn over frequently. Our results suggest that there is substantial unappreciated diversity in de novo protein evolution: many more may exist than have been previously appreciated; there may be divergent evolutionary trajectories; and de novo proteins may be gained and lost frequently. All in all, there may not exist a single characteristic model of de novo protein evolution, but rather complex origins and evolutionary trajectories for de novo proteins. Impact statementThe analysis of mass-spectrometry data for all possible open reading frames reveals protein evidence for evolutionarily young, unannotated proteins with distinct characters.

evolutionary biology↗

bioRxiv2022

Biological responses to terahertz radiation with different power density in primary hippocampal neurons

BackgroundTerahertz (THz) radiation is a valuable imaging and sensing tool which is widely used in industry and medicine. However, it biological effects including genotoxicity and cytotoxicity are not clear, particularly on the nervous system. In this study, we investigated how THz radiation with different frequency and intensity would affect the morphology, cell growth and function of rat hippocampal neurons in vitro. MethodsPrimary hippocampal neuronal cells were isolated from newborn Wistar rat pups and were exposed to THz radiation with the frequencies of 0.12 THz and 0.141 THz, at an power intensities of 10 mW/cm2 and 30 mW/cm2 respectively. The cellular activities were evaluated by Cell Counting Kit-8 after exposure for 10 min and 30 min. The cellular apoptosis was examined by Annexin V staining using flow cytometry and the ultrastructure was detected by electron microscopy. Moreover, the amount of amino acid in the cultured neurons was measured by high performance liquid chromatography (HPLC). ResultsNo obvious morphological changes, such as axon length and axon number, could be detected in primary neurons after exposure to 10mW/cm2 or 50 mW/cm2 THz for 30 min. However, the overall cellular activities were differentially affected by 10mW/cm2 and 50 mW/cm2 THz. Obvious cellular apoptosis was induced by both 10mW/cm2 and 50 mW/cm2 exposure. We also found that the amounts of most amino acids did not change significantly after exposure to these two types of THz radiation. ConclusionsThe effects of THz radiation on hippocampal neurons depend on frequency, power, exposure time as well as the measurement time after the exposure. These results will provide important information for further investigation of the effect of THz radiation on the nervous system.

neuroscience↗

bioRxiv2022

Hypoxia-induced tracheal elasticity in vector beetle facilitates the loading of pinewood nematode

Many pathogens rely on their insect vectors for transmission. Such pathogens are under selection to improve vector competence for their transmission by employing various tissue or cellular responses of vectors. However, whether pathogens can actively cause hypoxia in vectors and exploit hypoxia responses to promote their vector competence is still unknown. Fast dispersal of pinewood nematode (PWN), the causal agent for the destructive pine wilt disease and subsequent infection of pine trees is characterized by the high vector competence of pine sawyer beetles (Monochamus spp.), and a single beetle can harbor over 200,000 PWNs in its tracheal system. Here, we demonstrate that PWN loading activates hypoxia in tracheal system of the vector beetles. Both PWN loading and hypoxia enhanced tracheal elasticity and thickened the apical extracellular matrix (aECM) of the tracheal tubes while a notable upregulated expression of a resilin-like mucin protein Muc91C was observed at the aECM layer of PWN-loaded and hypoxic tracheal tubes. RNAi knockdown of Muc91C reduced tracheal elasticity and aECM thickness under hypoxia conditions and thus decreasing PWN loading. Our study suggests a crucial role of hypoxia-induced developmental responses in shaping vector tolerance to the pathogen and provides clues for potential molecular targets to control pathogen dissemination.

ecology↗

bioRxiv2022

Planting graphene quantum dots in PEGylated nanoparticles for enhanced and multimodal in vivo imaging of tumor

Photoluminescent graphene quantum dots (GQDs) have recently attracted considerable attention for biomedical applications owing to the interesting physicochemical and photophysical properties, and prominent biocompatibility and biosafety. However, although much progress has been achieved in therapy and in vitro bioimaging, broad and crucial in vivo fluorescence bioimaging and synergistically working with other nanomedicine are very challenging and limited. Herein, we in situ implanted GQDs in the PEGylated layer of nanoparticles (NPs) via a bottom-up approach to obtain the NPs (core)-GQDs-PEG multifunctional nanoprobe (NPC-GQDs-PEG), which prolonged the blood circulation of GQDs more than four times and increased the tumor accumulation 7~8 times than GQDs used alone. Under assisted by the flexible microscope, the GQDs were successfully used for in vivo real-time monitoring of local NPs pharmacokinetics, in vivo multimodality imaging, and fluorescence imaging-guided tumor surgery. The approach of implanting GQDs in PEGylated nanomedicine and synergistic working provide a new strategy for in vivo biomedical applications of GQDs.

cancer biology↗

bioRxiv2022

Efficient rescue of a newly classified Ebinur lake orthobunyavirus with GFP reporter and its application in rapid antiviral screening

Orthobunyaviruses have been reported to cause severe diseases in humans or animals, posing a threat to human health and social economy. Ebinur lake virus (EBIV) is a newly classified orthobunyavirus, which needs further intensive study and therapies to cope with its potential infection risk to human and animals. Here, through the reverse genetics system, the recombinant EBIV of wild type (rEBIV/WT) and NP-conjugated-eGFP (rEBIV/eGFP/S) were rescued for the application of the rapid antiviral drug screening. The eGFP fluorescence signal of the rEBIV/eGFP/S was stable in the process of successive passage in BHK-21 cells (over 10 passages) and this recombinant virus could replicate in various cell lines. Compared to the wild type EBIV, the rEBIV/eGFP/S caused the smaller plaques and its peak titers were lower, suggesting attenuation due to the eGFP insertion. Through the high-content screening (HCS) system, ribavirin showed an inhibitory effect on the rEBIV/eGFP/S with an EC50 of 21.91 M, while favipiravir did not inhibit, even at high concentrations. In addition, five of ninety-six natural compounds had antiviral against EBIV. The robust reverse genetics system for EBIV will facilitate investigation into replication and assembly mechanisms and assist drug and vaccine development.

molecular biology↗

bioRxiv2022

Mapping Multiple Factors Mediated Chromatin Interactions to Assess Regulatory Network and Dysregulation of Lung Cancer-Related Genes

Studies on the lung cancer genome are indispensable for developing a cure for lung cancer. Whole-genome resequencing, genome-wide association studies, and transcriptome sequencing have greatly improved our understanding of the cancer genome. However, dysregulation of long-range chromatin interactions in lung cancer remains poorly described. To better understand the three-dimensional (3D) genomic interaction features of the lung cancer genome, we used the A549 cell line as a model system. The generated high-resolution data revealed chromatin interactions associated with RNA polymerase II (RNAPII), CCCTC-binding factor (CTCF), enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2), and histone 3 lysine 27 trimethylation (H3K27me3) using specific antibodies and long-read chromatin interaction analysis by paired-end tag sequencing (ChIA-PET). The EZH2/H3K27me3-mediated interactions further silenced target genes, either through loops or domains, and showed distributions along the genome distinct from and complementary to those associated with RNAPII. We found that cancer-related genes were highly enriched in chromatin interactions. We identified abnormal interactions associated with oncogenes and tumor suppressors, such as additional repressive interactions on FOXO4 and promoter - promoter interactions between NF1 and RNF135. Knockout of abnormal interactions reversed the dysregulation of cancer-related genes, suggesting that chromatin interactions are essential for proper expression of lung cancer-related genes. These findings demonstrate the 3D landscape and gene regulatory relationships of the lung cancer genome.

genomics↗

bioRxiv2022

Phenethylamine-producing gut bacteria induces diarrhea-predominant irritable bowel syndrome by increasing serotonin biosynthesis

Despite the strong association between gut microbial dysbiosis, serotonin (5-HT) dysregulation and diarrhea-predominant irritable bowel syndrome (IBS-D), the mechanism by which changes in the gut microbiota contribute to the pathogenesis of IBS-D, particularly the role of dysregulated 5-HT production, remains unclear. The present study identified Ruminococcus gnavus in the human gut microbiota as a key risk factor of IBS-D. R. gnavus was significantly enriched in IBS-D patients and exhibited positive correlation with serum 5- HT level and severity of diarrhea symptoms. We showed that R. gnavus induced diarrhea-like symptoms in mice by promoting microbial shunting of essential aromatic amino acids to aromatic trace amines including phenethylamine and tryptamine, thereby stimulating the biosynthesis of peripheral 5-HT, a potent stimulator for gastrointestinal transit. This study identify gut-microbial metabolism of dietary amino acids as a cause of IBS-D and lays a foundation for developing novel therapeutic target for the treatment of IBS-D. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/483096v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@48400aorg.highwire.dtl.DTLVardef@1645aedorg.highwire.dtl.DTLVardef@18d878dorg.highwire.dtl.DTLVardef@be4b30_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2022

Gut microbiota-derived tryptamine impairs insulin sensitivity

Gut-microbiota plays a pivotal role in development of type 2 diabetes (T2D), yet the molecular mechanism remains elusive. Here, we show that tryptamine, a microbial metabolite of tryptophan, impairs glucose tolerance and insulin sensitivity. Tryptamine presents a higher level in monkeys with spontaneous diabetes and human with T2D and positively correlated with the glucose tolerance. In parallel, tryptamine level was suppressed by dietary fibers intervention in T2D subjects and negatively correlated with improvement of glucose tolerance. The inhibitory effect of tryptamine on insulin signaling as shown was dependent on a trace amine-associated receptor 1 (TAAR1)-extracellular signal-regulated kinase (ERK) signaling axis. Monoassociation of T2D-associated tryptamine-producing bacteria Ruminococcus gnavus impairs insulin sensitivity in pseudo germ-free mice. Our findings indicate gut microbiota-derived tryptamine contributes to the development of insulin resistance in T2D and may serve as a new target for intervention. Graphical Abstract O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

microbiology↗

bioRxiv2022

Rapidly evolving genes underlie Aedes aegypti mosquito reproductive resilience during drought

Female Aedes aegypti mosquitoes impose a severe global public health burden as vectors of multiple viral pathogens. Under optimal environmental conditions, Aedes aegypti females have access to human hosts that provide blood proteins for egg development, conspecific males that provide sperm for fertilization, and freshwater that serves as an egg-laying substrate suitable for offspring survival. As global temperatures rise, Aedes aegypti females are faced with climate challenges like intense droughts and intermittent precipitation, which create unpredictable, suboptimal conditions for egg-laying. Here we show that under drought-like conditions simulated in the laboratory, females retain mature eggs in their ovaries for extended periods, while maintaining the viability of these eggs until they can be laid in freshwater. Using transcriptomic and proteomic profiling of Aedes aegypti ovaries, we identify two previously uncharacterized genes named tweedledee and tweedledum, each encoding a small, secreted protein that both show ovary-enriched, temporally-restricted expression during egg retention. These genes are mosquito-specific, linked within a syntenic locus, and rapidly evolving under positive selection, raising the possibility that they serve an adaptive function. CRISPR-Cas9 deletion of both tweedledee and tweedledum demonstrates that they are specifically required for extended retention of viable eggs. These results highlight an elegant example of taxon-restricted genes at the heart of an important adaptation that equips Aedes aegypti females with "insurance" to flexibly extend their reproductive schedule without losing reproductive capacity, thus allowing this species to exploit unpredictable habitats in a changing world.

neuroscience↗