Project description:Replication of the eukaryotic genome requires the assembly of thousands of replisomes that must work in concert to accurately replicate a cell’s genetic and epigenetic information. Defining replisome-associated proteins is a key step in understanding how genomes are replicated and repaired in the context of chromatin to maintain genome stability. To identify replisome-associated proteins, we performed iPOND (Isolation of Proteins on Nascent DNA) coupled to quantitative mass spectrometry in Drosophila embryos and cultured cells. We identified 76 and 416 replisome-associated proteins in post-MZT embryos and Drosophila cultured S2 cells, respectively . By performing a targeted screen of a subset of these proteins, we demonstrate that BRWD3, a targeting specificity factor for the DDB1/Cul4 ubiquitin ligase complex (CRL4), functions at the replisome to promote replication fork progression and maintain genome stability. Altogether, our work provides a valuable resource for those interested in the DNA replication, repair and chromatin assembly during development.

2022-01-27 | PXD031165 | Pride

Maternal gene expression data from dMLL3/4-depleted Drosophila embryos

Project description:Analysis of Drosophila melanogaster early embryos (pre-zygotic genome activation) following the germ line-specific depletion of the dMLL3/4 histone methyltransferase (also known as Trr). These results provide insight into the molecular mechanisms responsible for the assembly of the zygotic genome at fertilization.

2018-07-12 | GSE108033 | GEO

Linker histone H1 regulates homeostasis of heterochromatin associated cRNAs [ChIP-seq 1]

Project description:Chromosomal RNAs (cRNAs) are a poorly understood fraction of cellular RNAs that co-purify with chromatin. Here we show that, in Drosophila, cRNAs constitute a heterogeneous group of RNA species that cover ~28% of the genome. Intriguingly, we found that cRNAs are highly enriched in heterochromatic transcripts. Our results show that heterochromatic cRNAs interact with the hnRNP A/B proteins hrp36 and hrp48 to assemble into RNP particles. We also show that depletion of linker histone dH1, a major component of chromatin, impairs assembly of hrp36 and hrp48 onto heterochromatic cRNAs. Concomitantly, impaired cRNAs assembly induces the accumulation of heterochromatic cRNAs and the formation of unscheduled RNA::DNA hybrids (R-loops). Linker histones H1 are known to regulate chromatin structure and compaction and, indeed, we show that dH1 depletion perturbs chromatin organization, reducing nucleosome occupancy and specifically increasing accessibility and 3D interactions within heterochromatin. These perturbations facilitate annealing of cRNAs to the DNA template, enhancing R-loops formation and cRNAs retention at heterochromatin. Altogether, these results unveil the unexpected contribution of linker histones to RNPs assembly and homeostasis of cRNAs.

2024-04-23 | GSE228067 | GEO

Linker histone H1 regulates homeostasis of heterochromatin associated cRNAs [ATAC-seq]

2024-04-23 | GSE228076 | GEO