Probing small ribosomal subunit RNA helix 45 acetylation across eukaryotic evolution.

NAT10 is an essential enzyme that catalyzes N4-acetylcytidine (ac4C) in eukaryotic transfer RNA and 18S ribosomal RNA. Recent studies suggested that rRNA acetylation is dependent on SNORD13, a box C/D small nucleolar RNA predicted to base-pair with 18S rRNA via two antisense elements. However, the selectivity of SNORD13-dependent cytidine acetylation and its relationship to NAT10's essential function remain to be defined.

When Bigger Is Better: 3D RNA Profiling of the Developing Head in the Catshark .

We report the adaptation of RNA tomography, a technique allowing spatially resolved, genome-wide expression profiling, to a species occupying a key phylogenetic position in gnathostomes, the catshark . We focused analysis on head explants at an embryonic stage, shortly following neural tube closure and of interest for a number of developmental processes, including early brain patterning, placode specification or the establishment of epithalamic asymmetry. As described in the zebrafish, we have sequenced RNAs extracted from serial sections along transverse, horizontal and sagittal planes, mapped the data onto a gene reference taking advantage of the high continuity genome recently released in the catshark, and projected read counts onto a digital model of the head obtained by confocal microscopy.

Prmt5 promotes vascular morphogenesis independently of its methyltransferase activity.

During development, the vertebrate vasculature undergoes major growth and remodeling. While the transcriptional cascade underlying blood vessel formation starts to be better characterized, little is known concerning the role and mode of action of epigenetic enzymes during this process. Here, we explored the role of the Protein Arginine Methyl Transferase Prmt5 in blood vessel formation as well as hematopoiesis using zebrafish as a model system.

CBP and P300 regulate distinct gene networks required for human primary myoblast differentiation and muscle integrity.

The acetyltransferases CBP and P300 have been implicated in myogenesis in mouse immortalized cell lines but these studies focused only on the expression of a handful of myogenic factors. Hence, the respective role of these two related cofactors and their impact at global scale on gene expression rewiring during primary myoblast differentiation remain unknown. Here, we characterised the gene networks regulated by these two epigenetic enzymes during human primary myoblast differentiation (HPM).

Robust Identification of Developmentally Active Endothelial Enhancers in Zebrafish Using FANS-Assisted ATAC-Seq.

Identification of tissue-specific and developmentally active enhancers provides insights into mechanisms that control gene expression during embryogenesis. However, robust detection of these regulatory elements remains challenging, especially in vertebrate genomes. Here, we apply fluorescent-activated nuclei sorting (FANS) followed by Assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-seq) to identify developmentally active endothelial enhancers in the zebrafish genome.

Vegfa signals through ERK to promote angiogenesis, but not artery differentiation.

Vascular endothelial growth factor a (Vegfa) is essential for blood vessel formation and can induce activation of numerous signaling effectors in endothelial cells. However, it is unclear how and where these function in developmental contexts during vascular morphogenesis. To address this issue, we have visualized activation of presumptive Vegfa effectors at single-cell resolution in zebrafish blood vessels.

Distinct Notch signaling outputs pattern the developing arterial system.

Differentiation of arteries and veins is essential for the development of a functional circulatory system. In vertebrate embryos, genetic manipulation of Notch signaling has demonstrated the importance of this pathway in driving artery endothelial cell differentiation. However, when and where Notch activation occurs to affect endothelial cell fate is less clear.

BMP signaling orchestrates photoreceptor specification in the zebrafish pineal gland in collaboration with Notch.

A variety of signaling pathways have been shown to regulate specification of neuronal subtype identity. However, the mechanisms by which future neurons simultaneously process information from multiple pathways to establish their identity remain poorly understood. The zebrafish pineal gland offers a simple system with which to address questions concerning the integration of signaling pathways during neural specification as it contains only two types of neurons - photoreceptors and projection neurons.

Notch resolves mixed neural identities in the zebrafish epiphysis.

Manipulation of Notch activity alters neuronal subtype identity in vertebrate neuronal lineages. Nonetheless, it remains controversial whether Notch activity diversifies cell fate by regulating the timing of neurogenesis or acts directly in neuronal subtype specification. Here, we address the role of Notch in the zebrafish epiphysis, a simple structure containing only two neural subtypes: projection neurons and photoreceptors.