Cell cycle-regulated transcriptional pausing of replication-dependent histone genes.

Coordinated expression of replication-dependent (RD) histones genes occurs within the Histone Locus Body (HLB) during S phase, but the molecular steps in transcription that are cell cycle regulated are unknown. We report that RNA Pol II promotes HLB formation and is enriched in the HLB outside of S phase, including G1-arrested cells that do not transcribe RD histone genes. In contrast, the transcription elongation factor Spt6 is enriched in HLBs only during S phase.

Directed stochasticity: Building biomolecular condensates in the right place.

Controlling biomolecular condensate formation within the nucleus is critical for genome function. In this issue, Xu et al. (https://doi.

Evidence for dual roles of histone H3 lysine 4 in antagonizing Polycomb group function and promoting target gene expression.

Tight control over cell identity gene expression is necessary for proper adult form and function. The opposing activities of Polycomb and trithorax complexes determine the on/off state of cell identity genes such as the Hox factors. Polycomb group complexes repress target genes, whereas trithorax group complexes are required for their expression.

Redesigning the Drosophila histone gene cluster: an improved genetic platform for spatiotemporal manipulation of histone function.

Mutating replication-dependent (RD) histone genes is an important tool for understanding chromatin-based epigenetic regulation. Deploying this tool in metazoans is particularly challenging because RD histones in these organisms are typically encoded by many genes, often located at multiple loci. Such gene arrangements make the ability to generate homogenous histone mutant genotypes by site-specific gene editing quite difficult.

Dual roles of histone H3 lysine-4 in antagonizing Polycomb group function and promoting target gene expression.

Tight control over cell identity gene expression is necessary for proper adult form and function. The opposing activities of Polycomb and trithorax complexes determine the ON/OFF state of targets like the Hox genes. Trithorax encodes a methyltransferase specific to histone H3 lysine-4 (H3K4).