Epi-microRNA mediated metabolic reprogramming counteracts hypoxia to preserve affinity maturation.

To increase antibody affinity against pathogens, positively selected GC-B cells initiate cell division in the light zone (LZ) of germinal centers (GCs). Among these, higher-affinity clones migrate to the dark zone (DZ) and vigorously proliferate by utilizing energy provided by oxidative phosphorylation (OXPHOS). However, it remains unknown how positively selected GC-B cells adapt their metabolism for cell division in the glycolysis-dominant, cell cycle arrest-inducing, hypoxic LZ microenvironment.

The PNUTS phosphatase complex controls transcription pause release.

Gene expression is regulated by controlling distinct steps of the transcriptional cycle, including initiation, pausing, elongation, and termination. Kinases phosphorylate RNA polymerase II (RNA Pol II) and associated factors to control transitions between these steps and to act as central gene regulatory nodes. Similarly, phosphatases that dephosphorylate these components are emerging as important regulators of transcription, although their roles remain less well understood.

The Polycomb system sustains promoters in a deep OFF state by limiting pre-initiation complex formation to counteract transcription.

The Polycomb system has fundamental roles in regulating gene expression during mammalian development. However, how it controls transcription to enable gene repression has remained enigmatic. Here, using rapid degron-based depletion coupled with live-cell transcription imaging and single-particle tracking, we show how the Polycomb system controls transcription in single cells.

Chromatin profiling identifies putative dual roles for H3K27me3 in regulating transposons and cell type-specific genes in choanoflagellates.

Gene expression is tightly controlled during animal development to allow the formation of specialized cell types. Our understanding of how animals evolved this exquisite regulatory control remains elusive, but evidence suggests that changes in chromatin-based mechanisms may have contributed. To investigate this possibility, here we examine chromatin-based gene regulatory features in the closest relatives of animals, choanoflagellates.

Extensive DNA methylome rearrangement during early lamprey embryogenesis.

DNA methylation (5mC) is a repressive gene regulatory mark widespread in vertebrate genomes, yet the developmental dynamics in which 5mC patterns are established vary across species. While mammals undergo two rounds of global 5mC erasure, teleosts, for example, exhibit localized maternal-to-paternal 5mC remodeling. Here, we studied 5mC dynamics during the embryonic development of sea lamprey, a jawless vertebrate which occupies a critical phylogenetic position as the sister group of the jawed vertebrates.