Biology subjects

Reimegard, J.

Publications and source records attributed to Reimegard, J..

4 recordsLinked to original sources

bioRxiv2025

Conserved molecular signatures of hygrosensory neurons in two dipteran species

Small poikilothermic animals like insects rely on environmental sensing for survival. The ability to detect humidity and temperature through specialized sensory neurons is particularly critical, allowing them to maintain water balance across diverse environments. While recent studies have identified key receptors associated with humidity sensing, our understanding of the broader molecular architecture underlying these sensory systems remains incomplete. Here, we conducted a comparative analysis of humidity receptor neurons (HRN) between the vinegar fly Drosophila melanogaster and the yellow fever mosquito Aedes aegypti. We identified 21 genes that define the molecular identity of HRNs. These genes encode proteins involved in transcriptional regulation, cellular signaling, enzymatic pathways and cellular organization. Through behavioral analysis, we demonstrate essential roles for three of these genes, the serotonin receptor 5-HT7, the transcription factor nubbin and the kinesin motor protein Kif19A are all required for humidity-guided behavior. The conservation of this molecular toolkit between species separated by over 200 million years of evolution suggests shared functional requirements for environmental sensing in insects. Our findings provide insights into fundamental principles of sensory neuron organization and oeer a framework for understanding how specialized sensory systems evolve and maintain their function.

animal behavior and cognition↗

bioRxiv2022

Comprehensive interrogation of a Drosophila embryonic patterning network reveals the impact of chromatin state on tissue-specific burst kinetics and RNA Polymerase II promoter-proximal pause release

Formation of tissue-specific transcriptional programs underlies multicellular development, but how the chromatin landscape influences transcription is not fully understood. Here we comprehensively resolve differential transcriptional and chromatin states during Drosophila dorsoventral (DV) patterning. We find that RNA Polymerase II pausing is established at DV promoters prior to zygotic genome activation (ZGA), that pausing persists irrespective of cell fate, but that release into productive elongation is tightly regulated and accompanied by tissue-specific P-TEFb recruitment. DV enhancers acquire distinct tissue-specific chromatin states through CBP-mediated histone acetylation that predict the transcriptional output of target genes, whereas promoter states are more tissue invariant. Transcriptome-wide inference of burst kinetics in different cell types revealed that while DV genes are generally characterized by a high burst size, either burst size or frequency can differ between tissues. The data suggest that pausing is established by pioneer transcription factors prior to ZGA and that release from pausing is imparted by enhancer chromatin state to regulate bursting in a tissue-specific manner in the early embryo. Our results uncover how developmental patterning is orchestrated by tissue-specific bursts of transcription from Pol II primed promoters in response to enhancer regulatory cues.

molecular biology↗

bioRxiv2020

Abundantly expressed class of non-coding RNAs conserved through the multicellular evolution of dictyostelid social amoebae

BackgroundAggregative multicellularity has evolved multiple times in diverse groups of eukaryotes. One of the most well-studied examples is the development of dictyostelid social amoebae, e.g. Dictyostelium discoideum. However, it is still poorly understood why multicellularity emerged in these amoebae while the great majority of other members of Amoebozoa are unicellular. Previously a novel type of non-coding RNA, Class I RNAs, was identified in D. discoideum and demonstrated to be important for normal multicellular development. In this study we investigated Class I RNA evolution and its connection to multicellular development. ResultsNew Class I RNA genes were identified by constructing a co-variance model combined with a scoring system based on conserved up-stream sequences. Multiple genes were predicted in representatives of each major group of Dictyostelia and expression analysis validated that our search approach can identify expressed Class I RNA genes with high accuracy and sensitivity. Further studies showed that Class I RNAs are ubiquitous in Dictyostelia and share several highly conserved structure and sequence motifs. Class I RNA genes appear to be unique to dictyostelid social amoebae since they could not be identified in searches in outgroup genomes, including the closest known relatives to Dictyostelia. ConclusionOur results show that Class I RNA is an ancient abundant class of ncRNAs, likely to have been present in the last common ancestor of Dictyostelia dating back at least 600 million years. Taken together, our current knowledge of Class I RNAs suggests that they may have been involved in evolution of multicellularity in Dictyostelia.

evolutionary biology↗

bioRxiv2019

Combined mRNA and protein single cell analysis in a dynamic cellular system using SPARC

Combined measurements of mRNA and protein expression in single cells enables in-depth analysis of cellular states. We present single-cell protein and RNA co-profiling (SPARC), an approach to simultaneously measure global mRNA and large sets of intracellular protein in individual cells. Using SPARC, we show that mRNA expression fails to accurately reflect protein abundance at the time of measurement in human embryonic stem cells, although the direction of changes of mRNA and protein expression are in agreement during cellular differentiation. Moreover, protein levels of transcription factors better predict their downstream effects than do the corresponding transcripts. We further show that changes of the balance between protein and mRNA expression levels can be applied to infer expression kinetic trajectories, revealing future states of individual cells. Finally, we highlight that mRNA expression may be more varied among cells than levels of the corresponding proteins. Overall, our results demonstrate that mRNA and protein measurements in single cells provide different and complementary information regarding cell states. Accordingly, SPARC can offer valuable insights in gene expression programs of single cells.

cell biology↗