Biology subjects

Jensen, K.

Publications and source records attributed to Jensen, K..

At least 19 recordsLinked to original sources

bioRxiv2026

Mapping bacterial cutinase sequence space by high-throughput screening reveals that PET hydrolysis is a rare property

Poly(ethylene terephthalate) (PET) is one of the most widely produced plastics, and enzymatic depolymerization offers a promising route to closed-loop recycling under mild conditions. However, most known bacterial PET hydrolases belong to a conserved canonical-fold cutinase family, leaving much of alpha/beta-hydrolase diversity unexplored. Here, we mapped bacterial cutinase sequence space by combining bioinformatics-guided sequence selection with high-throughput secretion screening in Bacillus subtilis. A library of 1,120 genes encoding 954 unique bacterial cutinases, spanning canonical- and minimal-fold families, was screened for activity on Impranil DLN and semicrystalline PET. We identified 156 secreted cutinases with polyester activity, broadly distributed across sequence space, but only ten showed detectable PET hydrolysis, all from the canonical-fold family. These PET hydrolases were active at 40-50{degrees}C, preferred alkaline pH, and showed moderate thermostability. Our results demonstrate that PET activity is rare among bacterial cutinases and provide a scalable workflow for discovering diverse enzyme starting points.

biochemistry↗

bioRxiv2026

Enkephalin constrains fear learning via volume transmission to the lateral amygdala

Fear learning involves the formation of associations between cues and aversive outcomes, a process that must be tightly regulated to prevent excessive or generalised fear. Dopamine release in the lateral amygdala (LA) drives fear acquisition, whereas endogenous opioids constrain it. However, whether opioids are dynamically released within the amygdala circuits during learning, and how they exert this control remain unclear. Here we show that met-enkephalin is locally released within the amygdala during auditory fear conditioning, with signals shifting from the aversive outcome to its predictive cue as learning progresses. The amygdalo-striatal transition zone (ASt), is the principal source of this enkephalin, released from medium spiny neurons receiving strong auditory thalamic input. This enkephalin spreads from the ASt to the LA via volume transmission. Selective knockdown in the ASt abolished opioid signals and enhanced fear learning, demonstrating that this diffuse signal constrains fear memory formation. We further show that enkephalin suppresses dopamine release in both the ASt and LA via {micro}-opioid receptors, identifying the ASt as a neuromodulator hub coordinating opioid and dopaminergic signalling across amygdala fear circuits. Although demonstrated here for auditory fear learning, the ASt receives multimodal sensory input, suggesting a broader mechanism through which sensory experience recruits enkephalin release to gate associative learning

neuroscience↗

bioRxiv2026

Targeted depletion of CD38+ autoreactive T cells prevents type 1 diabetes

Type 1 diabetes (T1D) is caused by T cell-mediated autoimmune destruction of insulin-producing islet {beta}-cells. Treatment with T-cell depleting therapies delays the progression of stage 2 and 3 T1D, but these agents exert broad immunosuppressive effects on T cell populations, including T regulatory cells (Tregs), which are key in promoting immune tolerance. We evaluated non-obese diabetic (NOD) mice and recently diagnosed T1D patients and identified CD38 as a marker for pathogenic T cell populations. Using adoptive T-cell transfer in Recombination Activating Gene 1 knockout NOD mice and in a humanized mouse model of autoimmune diabetes, we demonstrated that CD38-expressing autoreactive T cells drive diabetes pathogenesis. Furthermore, we found that selective depletion of CD38+ cells, using an anti-CD38 monoclonal antibody (mAb), prevents insulitis and diabetes onset without depleting CD4+CD25+ Tregs. Administration of anti-CD38 mAb did not adversely affect islet function and may selectively eliminate immunogenic senescent islet {beta}-cells. These results support the strategy of selectively depleting diabetogenic T cells using an anti-CD38 mAb to treat T1D and restore immune tolerance. Therefore, transient depletion of autoreactive T cells using anti-CD38 mAb may provide a novel strategy to prevent or abrogate {beta}-cell autoimmunity in T1D. One sentence summaryPathogenic autoreactive are characterized by CD38 overexpression, and their selective depletion with anti-CD38 monoclonal antibody prevents autoimmune diabetes.

immunology↗

bioRxiv2026

A high-resolution atlas of cattle regulatory variants and their cross-species activity in matched human cells

Identifying causal noncoding variants underlying complex traits in cattle remains challenging because high-resolution functional maps of regulatory variation are lacking. Here we combine massively parallel reporter assays with graph genomics to measure autonomous transcriptional activity from >1.5 billion DNA fragments spanning both cattle subspecies. In primary bovine cells, we assay >15 million variants and identify >150,000 expression-modulating variants enriched at cattle eQTL and GWAS loci. This enables the refinement of broad association signals to small sets of candidate functional regulatory variants. Our haplotype-aware framework captures rare, multi-allelic and tightly linked variants poorly resolved by conventional eQTL studies, and quantifies the disproportionate impact of larger variants on transcription. Furthermore, we use these data to train a deep-learning model that successfully predicts bovine promoter activity directly from sequence. Profiling the same cattle DNA in matched primary human cells reveals widespread conservation of promoter and enhancer activity, allelic effects and regulatory grammar, supporting the transfer of annotations and models across species. However, species-dependent effects are enriched in evolutionarily young sequences and p53-family motifs, highlighting the limits to simple cross-species extrapolation. Together, these data provide a high-resolution atlas of cattle regulatory variation and a framework for prioritising causal noncoding variants for cattle trait improvement.

genetics↗

bioRxiv2026

A transparent window into the rhizosphere: a simplified workflow for spatially resolved soil metabolomics

Root exudates play a central role in nutrient cycling, microbial recruitment, and plant-plant interactions, yet most experimental approaches for analyzing exudate chemistry rely on sterile hydroponic systems that poorly represent soil conditions. We present a low-cost, open-source, 3D-printed rhizobox platform and associated workflow that enable non-destructive root imaging and targeted rhizosphere soil sampling for LC-MS based metabolomics under realistic soil conditions. The design integrates a transparent removable window for repeated root observations, a defined soil volume to support spatially explicit sampling, and a blank-informed data-processing pipeline to distinguish plant-derived metabolites from soil and construction material background. We validated the system using the model plants Arabidopsis thaliana (Col-0) and Phragmites australis. We demonstrate reliable plant growth and consistent root development across the imaging window. We also show robust detection of species-specific rhizosphere metabolite profiles, with minimal variation in the vertical or temporal dimensions relative to the strong species effects. We further illustrate the application of the workflow in a factorial experiment manipulating social context (solo vs. conspecific pairs) and short-term heat stress in A. thaliana, showing that the approach is sensitive to treatment-associated changes in metabolite richness, diversity, and chemical composition in soil. The complete protocol, from rhizobox fabrication and assembly to soil extraction, LC-MS acquisition, and data curation can be implemented within 4-6 weeks using standard laboratory equipment and openly available design files. By combining ecological realism with analytical control, this workflow provides a broadly applicable method for quantifying rhizosphere metabolite dynamics across species, treatments, and spatial sampling zones, facilitating experimental studies of below-ground chemical processes in plant ecology.

plant biology↗

bioRxiv2025

Genetic Influences on Neural Responses in Placebo Analgesia Circuitry

Placebo analgesia is a well-established medical phenomenon with overlapping neural representations between humans and rodents, but the genetic contribution to this conserved neural circuitry remains unknown. Using functional brain imaging in 305 monozygotic and dizygotic twins, we quantified the heritability of neural activation in placebo analgesia brain circuity during evoked pain, including the rostral anterior cingulate cortex, brainstem and cerebellum, using the ACE model. Neural responses showed significant heritability, with additive genetics accounting for 21 to 49% of the variance (A = 0.21-0.49), indicating that genetics have a moderate effect on pain-evoked brain activity within the placebo analgesia circuitry. For the first time, our findings reveal a heritable component of the neural network supporting placebo analgesia. By linking genetic variations to neural responses in placebo analgesia circuitry, this study bridges human and preclinical research and opens new ways for improving clinical trial methodology and tailoring pain therapies to individual genetic profiles.

neuroscience↗

bioRxiv2025

Using gas exchange measurements to monitor growth, energy expenditure, and body composition of black soldier fly larvae (Hermetia illucens) on diets varying in protein-to-carbohydrate ratio

Optimizing black soldier fly larvae (BSFL) production requires a better understanding of how diet composition shapes growth, nutrient allocation, and metabolic efficiency. This study investigated whether respiratory measurements could serve as predictive, non-invasive tools for BSFL performance on diets differing in protein-to-carbohydrate (P:C) ratio. Larvae were reared for seven days on four experimental diets, with growth, survival, gas exchange (O2 consumption, CO2 production, respiratory exchange ratio (RER)), and body composition (crude protein and lipid contents) measured across seven replicates per treatment. O2 consumption correlated strongly with final larval biomass, while RER was closely associated with protein and lipid deposition. Larvae on low-protein, high-carbohydrate diets accumulated proportionally more lipid, whereas protein-rich diets increased crude protein content but required higher energetic investment. This demonstrates that lipid-rich larvae grew more efficient in energetic terms per unit accumulated biomass than protein-rich larvae. Across diets, gas exchange variables reliably reflected growth dynamics, metabolic activity, and nutrient assimilation. Integrating respirometry into rearing systems could enable real-time monitoring of insect biomass yield and nutrient composition.

physiology↗

bioRxiv2025

Consequences of dietary amino acid imbalance on growth and gas exchange in black soldier fly (Hermetia illucens) larvae

Black soldier fly larvae (Hermetia illucens (L.); BSFL) production relies on efficient nutrient conversion into protein-rich biomass to ensure sustainability and economic viability. While the effects of dietary protein content and macronutrient ratios are well described, the metabolic costs of providing an imbalanced essential amino acid (EAA) supply in dietary proteins remain poorly understood. We examined how dietary EAA imbalance affects growth, metabolism, and energy allocation in BSFL. Larvae were reared on a reference diet (chicken feed) and three isonitrogenous, semi-synthetic diets: one balanced diet matching the EAA profile of the reference, and two unbalanced diets selectively deficient in either leucine, phenylalanine, and threonine or isoleucine, lysine, and tryptophan. Using open flow respirometry, daily growth monitoring, and biochemical analysis, we quantified gas exchange, body composition, and the energetic costs of biomass and protein deposition. EAA imbalance delayed development, reduced growth and protein content, and promoted lipid accumulation, while O2 consumption and CO2 production were reduced and respiratory exchange ratios exceeded 1.0, indicating elevated lipogenesis. Metabolic costs per unit protein deposited were higher on EAA-deficient diets (up to 3.63 kJ per kJ protein), reflecting inefficient amino acid utilisation. In contrast, the balanced diet supported more efficient protein deposition at a lower energetic cost (2.73 kJ per kJ protein). Our findings demonstrate that suboptimal dietary EAA profiles reduce metabolic efficiency in BSFL. Quantifying the physiological costs of amino acid imbalance provides benchmarks to guide feed formulations in insect production systems to minimise input costs and maximise the nutritional quality and quantity of larval output.

physiology↗

bioRxiv2025

The cow udder is a potential mixing vessel for influenza A viruses

The incursion of high pathogenicity avian influenza A virus (IAV) into US dairy cows is unprecedented in the era of molecular diagnosis and pathogen sequencing. This raises questions over the likelihood of further outbreaks and whether dairy cattle could be a "mixing vessel" for novel strains of IAV. Using a panel of BSL2-safe reassortant viruses representing clade 2.3.4.4b H5 epizootic lineages circulating since 2020, we found that a cow B3.13 isolate displayed enhanced replication in cow mammary gland cells, along with increased viral polymerase activity and stronger interferon antagonism in cow cells compared to an earlier EA-2020-C genotype virus. However, multiple avian and mammalian IAV strains, including other clade 2.3.4.4b high pathogenicity genotypes, were replication competent in bovine cells, particularly those of the mammary gland, suggesting that there is a diverse circulating IAV pool with the potential to infect cows. Moreover, we show that cow mammary cells co-express -2,3 and -2,6 - linked sialic acids, and are susceptible to co-infection with human and avian IAVs. We conclude that the US cow influenza outbreak does not simply reflect a unique adaptation of the B3.13 genotype virus; rather, the bovine udder represents a permissive niche for IAV and a plausible site for reassortment, underscoring its potential role in generating novel influenza viruses with pandemic risk.

microbiology↗

bioRxiv2025

Regulation of a nickel tolerance operon conserved in Mesorhizobium strains from serpentine soils

The Mesorhizobium nre (nickel resistance) operon has previously been shown to mediate Ni tolerance in serpentine soils with naturally high concentrations of this transition metal. In most serpentine-derived strains evaluated, the putative efflux genes nreX and nreY are conserved, along with a small gene (nreA) encoding a CsoR/RcnR-family transcriptional regulator. CsoR/RcnR-family regulators are small (around 100 amino acids in length), they bind transition metals, and they use an unconventional and poorly understood DNA-binding mechanism. NreA is 93 amino acids in length and belongs to a poorly characterized clade within the CsoR/RcnR family. This investigation is focused on regulatory DNA elements that functionally interact with Mesorhizobium NreA, as well as amino acid residues in NreA that influence its regulatory activity. We show that NreA is a transcriptional repressor that is responsive to exogenous Ni. The Ni-responsive promoter is immediately upstream of the nreAXY operon, resulting in a leaderless transcript. A partially palindromic operator sequence occupies the spacer region between the -35 and -10 promoter elements. Mutational analysis of the operator highlights functionally crucial base pairs occupying opposite ends of the palindromic operator. Changes to conserved residues in the NreA polypeptide result in varying effects, with changes predicted to prevent Ni binding leading to a super-repressor phenotype. Structural modeling of the NreA-operator complex provides a plausible mechanism for DNA binding by a tetrameric form of NreA, with DNA contact sites along a positively charged surface, and the modeled contact sites agree well with the mutational analysis. IMPORTANCEBacteria employ diverse mechanisms for maintaining optimal intracellular levels of bioactive metals. Isolates of Mesorhizobium bacteria from nickel-rich serpentine soils possess a small genetic region controlling Ni efflux. This region is subject to transcriptional regulation via the small repressor protein NreA. In this work, the essential components of the NreA protein and the DNA operator with which it interacts are defined, enabling potential adaptation of this system for metal sensing or other technologies requiring a compact inducible gene expression module.

microbiology↗

bioRxiv2025

Reshaping the progranulin/sortilin interaction for targeted degradation of extracellular proteins

Targeted protein degradation (TPD) using PROteolysis TArgeting Chimeras (PROTACs) is a rapidly emerging therapeutic strategy for difficult-to-drug cytosolic proteins. PROTACs are heterobifunctional small molecules that bridge the target with an E3 ubiquitin ligase, destining it for degradation by the proteasome. They have the potential to be orally available and to act catalytically, switching the pharmacology from occupancy-driven to event-driven (1-3). Here we present a strategy for targeted degradation of extracellular proteins by reshaping the interaction between the broadly expressed lysosome sorting receptor sortilin and its ligand progranulin for engineering SORtilin-based lysosome TArgeting Chimeras (SORTACs). SORTACs induce ternary complex formation with the target and sortilin, followed by endocytosis and lysosomal degradation. SORTAC activity can be genetically encoded as demonstrated by converting an IgG binding nanobody to an IgG degrading nanobody or by chemical conjugation, enabling single step conversion of therapeutic antibodies from binding their target to driving its degradation. Importantly, using structure-based design, we generated small molecule SORTACs against the inflammatory cytokine TNFa with nanomolar range potency and with physicochemical properties like PROTACs. Our results demonstrate that SORTACs constitute a versatile and highly modular platform for rapid generation of degraders of in theory any extracellular target and with the potential to have wide impact in drug discovery.

biochemistry↗

bioRxiv2024

Evidence for white matter intrinsic connectivity networks at rest and during a task: a large-scale study and templates

Understanding white matter (WM) functional connectivity is crucial for unraveling brain function and dysfunction. In this study, we present a novel WM intrinsic connectivity network (ICN) template derived from over 100,000 fMRI scans, identifying 97 robust WM ICNs using spatially constrained independent component analysis (scICA). This WM template, combined with a previously identified gray matter (GM) ICN template from the same dataset, was applied to analyze a resting-state fMRI (rs-fMRI) dataset from the Bipolar-Schizophrenia Network on Intermediate Phenotypes 2 (BSNIP2; 590 subjects) and a task-based fMRI dataset from the MIND Clinical Imaging Consortium (MCIC; 75 subjects). Our analysis highlights distinct spatial maps for WM and GM ICNs, with WM ICNs showing higher frequency profiles. Modular structure within WM ICNs and interactions between WM and GM modules were identified. Task-based fMRI revealed event-related BOLD signals in WM ICNs, particularly within the corticospinal tract, lateralized to finger movement. Notable differences in static functional network connectivity (sFNC) matrices were observed between controls (HC) and schizophrenia (SZ) subjects in both WM and GM networks. This open-source WM NeuroMark template and automated pipeline offer a powerful tool for advancing WM connectivity research across diverse datasets.

neuroscience↗

bioRxiv2024

Targeting the untargeted: Uncovering the chemical complexity of root exudates

The chemical complexity of root exudates has garnered significant attention in recent years, yet critical gaps remain in understanding the full scope of root exudate chemical variation across the plant kingdom. To address this, we conducted a systematic review of 57 studies, comprising 124 experiments, aimed at evaluating current methodologies and findings in untargeted root exudate chemical analysis. Our review revealed that hydroponic (44%) and soil-hydroponic hybrid (32%) sampling approaches, primarily utilising water as the collection medium, were the most common experimental setups. Liquid chromatography-mass spectrometry (LC-MS) was the predominant analytical technique used in 54% of the studies, followed by gas chromatography-mass spectrometry (GC-MS) in 31%. The average number of metabolites identified per analysis was 960, though the number of annotated metabolites varied considerably. Shikimates, phenylpropanoids, and carbohydrates were the most frequently identified classes, with their relative abundances varying widely. Several methodological challenges were highlighted, including inconsistencies in sampling techniques, underrepresentation of non-crop plants, and incomplete chemical annotation. To address these limitations, we propose a framework emphasising the need for representative exudate sampling, the use of multiple analytical approaches, the development of advanced bioinformatics tools, and the integration of these findings to enhance our understanding of root exudates and their ecological functions.

ecology↗

bioRxiv2024

Controlled and polygynous mating in the black soldier fly: advancing breeding programs through quantitative genetic designs

In animal breeding programs, utilizing quantitative genetic designs such as the full-/half-sibling design is fundamental. A full-/half-sibling design demands that mating can be controlled, and individuals can be tracked, enabling construction of a pedigree. In nature, black soldier fly (Hermetia illucens (L.)) males are reported to gather in lekking groups to engage in competitive displays and courtship rituals before mating, and this lekking behavior is described as crucial for mating in this species. We show that a randomly chosen male and a randomly chosen virgin female can readily mate under LED lights in a small container at 28 {degrees}C and 70% RH, demonstrating the ability to mate selected pairs. For males given access to four females, all mated and the time until first mating was considerably shorter than for males given only one female, where 80% of the males mated. Furthermore, when adding four virgin females to a single male, males successfully mated all four females in 52% of cases within our four-hour trial, with 96% of males mating at least twice. Number of matings observed for a male correlated with the number of females from the container that laid an egg clutch, and almost all egg clutches produced offspring. Observed mating thus lead to fertilization, and consecutive matings were with new females resulting in full- and half-sibling offspring. Males with four females that mated a second female did so at a median time of less than three minutes upon ending previous mating, showing that polygynous mating occurred rapidly in this setup. Our findings pave the way for moving H. illucens breeding programs beyond mass selection towards advanced selective breeding designs where controlled mating is typically required. Such designs enable selection for multiple traits simultaneously while controlling inbreeding and can drastically increase rates of selection responses compared to mass selection.

animal behavior and cognition↗

bioRxiv2024

Design principles of small intestinal crypt maintenance

The intestinal epithelium has a remarkably high turnover in homeostasis. It remains unresolved how turnover is orchestrated at the cellular level and how the behaviour of stem and progenitor cells ensures tissue maintenance. To address this, we combined quantitative fate mapping in three complementary mouse models with mathematical modelling and single-cell RNA sequencing. Our integrated approach generated a spatially and temporally defined model of crypt maintenance that is based on two cycling populations: crypt-based columnar (CBC) and transit amplifying (TA) cells. Validation experiments substantiated the predictions from the model revealing TA cells as the major contributor to the absorptive lineage, while balanced CBC cell fate choices controlled the numbers of cells in the secretory lineage. By unravelling these mechanisms, we gain insights into the process of tissue turnover and provide direct evidence to support the notion of CBC cells as the major driver of the intestinal epithelium replenishment. HighlightsO_LISpatially and temporally resolved cellular model of small intestinal crypt maintenance. C_LIO_LIStem cells exhibit predisposition towards secretory fate. C_LIO_LISecretory lineage has a limited contribution to the high turnover of intestinal epithelium. C_LIO_LICellular differentiation within the crypt occurs rapidly within 72 hours. C_LI

cell biology↗

bioRxiv2024

Soil organic carbon stocks and stabilization mechanisms in tidal marshes along estuarine gradients

Tidal marshes store large amounts of soil organic carbon (SOC), however, little is known on SOC stabilization mechanisms in these ecosystems. In estuarine marshes, SOC storage is dominated by a complex interaction of tidal inundation and salinity with biotic ecosystem components, leading to strong spatio-temporal variations within estuaries. Our aim was to assess (i) SOC stocks, (ii) SOC stabilization mechanisms (aggregation and mineral-association), and (iii) their environmental drivers along estuarine gradients. We analyzed SOC stocks and SOC density fractions in topsoil (0-10 cm) and subsoil (10-30 cm) of three marsh zones representing three flooding regimes (daily, monthly, yearly) in three marsh types along the salinity gradient (salt, brackish, freshwater) of the Elbe Estuary, Germany. Increasing salinity and flooding reduced SOC stocks 0-30 cm (9.3-74.6 t ha-1), which was related to decreasing plant biomass and soil texture. Mineral-associated organic matter (CMAOM) was the largest SOC fraction (59% of total SOC), followed by aggregate-occluded organic matter (CoPOM) (24%) and free particulate organic matter (CfPOM) (16%). The CMAOM amount in topsoils decreased downstream with increasing salinity, reflecting decreasing fine-texture along the estuary. The amount of CoPOM was higher in topsoils and high marshes, indicating negative effects of flooding on aggregation. The relative proportion of CfPOM (% of total SOC) increased with increasing flooding frequency and reducing soil conditions. Our results underline the importance of estuarine gradients as drivers of SOC storage and stabilization. Climate-change induced sea-level rise and variations in salinity might reduce SOC storage and stabilization in estuaries.

ecology↗

bioRxiv2024

Partitioning biota along the Elbe River estuary: where are the community transitions?

Estuarine zonation and community assemblages are frequently correlated with salinity, although the extent or nature of this correlation varies considerably among the published studies. While a smooth transition in biological communities is often conceptualized in association with estuarine fresh, brackish, and marine conditions, many studies have shown more distinct communities and the altogether absence of a brackish community. We explore these viewpoints in light of plant observations and soil and aquatic microbial analyses from permanent plots established on the Elbe River Estuary of northern Germany. Generally, two distinct communities were observed, a polyhaline assemblage towards the mouth of the system, and another that was associated with both the fresh and brackish mesohaline regimes further upriver. This was most pronounced among plant and soil bacteria communities, while aquatic 16S assemblages reflected little distinction at all. The proportion of marine classified taxa declined from the mouth to upriver and suggests that while the transition from marine to brackish or fresh vegetation falls within the sampled area, the same transition for microbial taxa could not be observed and may be further upriver. Thus, although we were able to identify two distinct communities, the "limit" of marine taxa was only evident for vegetation. While tidal and weather-related hydrology, as well as soil properties were also influential in distinguishing the communities, much of the variance remains unexplained. Further sampling, classification, and partitioning is necessary to determine the origin and/or autochthonous habitat, if any, for the Elbe River estuarine taxa. Geographic boundsbottom left: 53.556216{degrees}N, 8.824398{degrees}E top right: 53.917760 {degrees}N, 10.155669 {degrees}E

ecology↗

bioRxiv2024

Endo-reduplication in mouse liver after conditional mutation of ORC2 and combined mutation of ORC1 and ORC2

The six subunit ORC is essential for initiation of DNA replication in eukaryotes. Cancer cell-lines in culture can survive and replicate DNA replication after genetic inactivation of individual ORC subunits, ORC1, ORC2 or ORC5. In primary cells, ORC1 was dispensable in the mouse liver for endo-reduplication, but this could be explained by the ORC1 homolog, CDC6, substituting for ORC1 to restore functional ORC. Here, we have created mice with a conditional deletion of ORC2, which does not have a homolog. Although mouse embryo fibroblasts require ORC2 for proliferation, mouse hepatocytes synthesize DNA in cell culture and endo-reduplicate in vivo without ORC2. Mouse livers endo-reduplicate after simultaneous deletion of ORC1 and ORC2 both during normal development and after partial hepatectomy. Since endo-reduplication initiates DNA synthesis like normal S phase replication these results unequivocally indicate that primary cells, like cancer cell lines, can load MCM2-7 and initiate replication without ORC.

genetics↗