In Nature this week, a team of researchers from across the US present a comprehensive analysis of the genome-wide chromatin landscape of Drosophila melanogaster, based on 18 histone modifications and summarized by nine prevalent combinatorial patterns. Active genes display distinct chromatin signatures that are correlated with "disparate gene lengths, exon patterns, regulatory functions and genomic contexts," the authors write. "We also demonstrate a diversity of signatures among Polycomb targets that include a subset with paused polymerase."
Also in Nature, researchers in China and Missouri report that the neurotransmitter 5-hydroxytryptamine is required for male sexual preference. In a study of male mice, the researchers found that wild-type male mice preferred females over males, but males lacking central serotonergic neutrons lost sexual preference. "A role for 5-HT was demonstrated by the phenotype of mice lacking tryptophan hydroxylase 2 (Tph2), which is required for the first step of 5-HT synthesis in the brain," the authors write. "Thirty-five minutes after the injection of the intermediate 5-hydroxytryptophan (5-HTP), which circumvented Tph2 to restore 5-HT to the wild-type level, adult Tph2 knockout mice also preferred females over males."
Researchers in Massachusetts present their map and analysis of chromatin state dynamics in nine human cell types in Nature this week. The researchers focused on cell-type-specific patterns of promoters and enhancers' defined multi-cell activity profiles for chromatin state, gene expression, regulatory motif enrichment and regulator expression; and used correlations between the resulting profiles to link enhancers to putative target genes and predict the cell-type-specific activators and repressors that modulate them. "The resulting annotations and regulatory predictions have implications for the interpretation of genome-wide association studies," the authors write. "Our study presents a general framework for deciphering cis-regulatory connections and their roles in disease."
Finally in Nature this week, a team of researchers presents the developmental transcriptome of Drosophila melanogaster. Using RNA-seq, tiling microarrays, and cDNA sequencing, the researchers explore the transcriptome of 30 difference developmental stages, and identified 111,195 new elements, including thousands of genes, transcripts, exons, and protein isoforms that had gone undiscovered by conventional experimental approaches. "These data substantially expand the number of known transcribed elements in the Drosophila genome and provide a high-resolution view of transcriptome dynamics throughout development," the authors write.