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Wilson, M. J.

Publications and source records attributed to Wilson, M. J..

3 recordsLinked to original sources

Genome-wide analysis of H3K4me3 and H3K27me3 modifications throughout the mouse urogenital ridge at E11.5.

In mammals, the adrenal gland, testis and ovary arise from a common progenitor tissue known as the urogenital ridge (UGR). This small population of cells will adopt a number of different cell fates following sex determination, including forming the precursors of somatic cells (such as Sertoli and granulosa cells) and steroidogenic cells. In addition, this tissues also contains the Wolffian and Mullerian ducts that later form components of the reproductive tracts. A potential mechanism to maintain developmental plasticity of the UGR until gonad formation is through the epigenetic modification of histone proteins.\n\nIn order to provide a resource for future studies, we used chromatin immunoprecipitation followed by high throughput sequencing (ChIP-seq) for two histone modifications, H3K4me3 and H3K27me3, in the E11.5 mouse UGR. These marks are both known to reflect the active, repressive or a poised chromatin state. We found that enrichment for each histone mark reflected transcriptional activity in precursor cells of the developing gonad. From the analysis of potential enhancer/regulator peak regions for DNA binding motifs, we identified several candidate transcription factors that may contribute to gonadal cell lineage specification. We additionally identified signaling pathway genes that are targeted by both chromatin modifications. Together, these datasets provide a useful resource for investigating gene regulatory networks functioning during UGR development at E11.5.

developmental biology

De novo draft assembly of the Botrylloides leachii genome provides further insight into tunicate evolution.

Tunicates are marine invertebrates that compose the closest phylogenetic group to the vertebrates. This chordate subphylum contains a particularly diverse range of reproductive methods, regenerative abilities and life-history strategies. Consequently, tunicates provide an extraordinary perspective into the emergence and diversity of chordate traits. To gain further insights into the evolution of the tunicate phylum, we have sequenced the genome of the colonial Stolidobranchian Botrylloides leachii.\n\nWe have produced a high-quality (90 % BUSCO genes) 159 Mb assembly, containing 82 % of the predicted total 194 Mb genomic content. The B. leachii genome is much smaller than that of Botryllus schlosseri (725 Mb), but comparable to those of Ciona robusta and Molgula oculata (both 160 Mb). We performed an orthologous clustering between five tunicate genomes that highlights sets of genes specific to some species, including a large group unique to colonial ascidians with gene ontology terms including cell communication and immune response.\n\nBy analysing the structure and composition of the conserved gene clusters, we identified many examples of multiple cluster breaks and gene dispersion, suggesting that several lineage-specific genome rearrangements occurred during tunicate evolution. In addition, we investigate lineage-specific gene gain and loss within the Wnt, Notch and retinoic acid pathways. Such examples of genetic change within these highly evolutionary conserved pathways commonly associated with regeneration and development may underlie some of the diverse regenerative abilities observed in the tunicate subphylum. These results supports the widely held view that tunicate genomes are evolving particularly rapidly.

genomics

Histological and haematological analysis of the ascidian Botrylloides leachii (Savigny, 1816) during whole-body regeneration

Abstract (250 words)Whole-body regeneration, the formation of an entire adult from only a small fragment of its own tissue, is extremely rare among chordates. Exceptionally, in the colonial ascidian Botrylloides leachii, a fully functional adult is formed from their common vascular system, upon ablation of all adults from the colony, in just 10 days thanks to their high blastogenetic potential. While previous studies have identified key genetic markers and morphological changes, no study has yet focused on the haematological aspects of regeneration despite the major involvement of the remaining vascular system and the contained haemocytes in this process. To dissect this process, we analysed colony blood flow patterns using time-lapse microscopy to obtain a quantitative description of the velocity, reversal pattern, and average distance travelled by haemocytes. We also observed that flows present during regeneration are powered by temporally and spatially synchronized contractions of the terminal ampullae. In addition, we revised previous studies on B. leachii haematology as well as asexual development using histological sectioning, and compared the role of haemocytes during whole-body regeneration. We found that regeneration starts with a rapid healing response characterized by blood clotting and infiltration of immunocytes, followed by increased activity of haemoblasts, recruitment of macrophage-like cells for clearing the tissues of debris, and their subsequent disappearance from the circulation concomitant with the maturation of a single regenerated adult. Overall, we provide a uniquely detailed account of the haematological properties of regenerating B. leachii colonies, providing novel lines of inquiry towards the decipherment of regeneration in chordates.

cell biology