The kinase Rio1 and a ribosome collision-dependent decay pathway survey the integrity of 18S rRNA cleavage.

The 18S rRNA sequence is highly conserved, particularly at its 3'-end, which is formed by the endonuclease Nob1. How Nob1 identifies its target sequence is not known, and in vitro experiments have shown Nob1 to be error-prone. Moreover, the sequence around the 3'-end is degenerate with similar sites nearby.

Spatiotemporal resolution of germinal center Tfh cell differentiation and divergence from central memory CD4 T cell fate.

Follicular helper T (Tfh) cells are essential for germinal center (GC) B cell responses. However, it is not clear which PD-1CXCR5Bcl6CD4 T cells will differentiate into PD-1CXCR5Bcl6 GC-Tfh cells and how GC-Tfh cell differentiation is regulated. Here, we report that the sustained Tigit expression in PD-1CXCR5CD4 T cells marks the precursor Tfh (pre-Tfh) to GC-Tfh transition, whereas TigitPD-1CXCR5CD4 T cells upregulate IL-7Rα to become CXCR5CD4 T memory cells with or without CCR7.

Mll1 pioneers histone H3K4me3 deposition and promotes formation of CD8 T stem cell memory.

CD8 T cells with stem cell-like properties (T ) sustain adaptive immunity to intracellular pathogens and tumors. However, the developmental origins and chromatin regulatory factors (CRFs) that establish their differentiation are unclear. Using an RNA interference screen of all CRFs we discovered the histone methylase Mll1 was required during T cell receptor (TCR) stimulation for development of a T precursor state and mature memory (T ) cells, but not short-lived or transitory effector cell-like states, in response to viral infections and tumors.

The chaperone protein p32 stabilizes HIV-1 Tat and strengthens the p-TEFb/RNAPII/TAR complex promoting HIV transcription elongation.

HIV gene expression is modulated by the combinatorial activity of the HIV transcriptional activator, Tat, host transcription factors, and chromatin remodeling complexes. To identify host factors regulating HIV transcription, we used specific single-guide RNAs and endonuclease-deficient Cas9 to perform chromatin affinity purification of the integrated HIV promoter followed by mass spectrometry. The scaffold protein, p32, also called ASF/SF2 splicing factor-associated protein, was identified among the top enriched factors present in actively transcribing HIV promoters but absent in silenced ones.

The Transcription Factor YY-1 Is an Essential Regulator of T Follicular Helper Cell Differentiation.

T follicular helper (T) cells are a specialized subset of CD4 T cells that deliver critical help signals to B cells for the production of high-affinity Abs. Understanding the genetic program regulating T differentiation is critical if one wants to manipulate T cells during vaccination. A large number of transcription factor (TFs) involved in the regulation of T differentiation have been characterized.

Bromodomain protein BRD4 directs and sustains CD8 T cell differentiation during infection.

In response to infection, pathogen-specific CD8 T cells differentiate into functionally diverse effector and memory T cell populations critical for resolving disease and providing durable immunity. Through small-molecule inhibition, RNAi studies, and induced genetic deletion, we reveal an essential role for the chromatin modifier and BET family member BRD4 in supporting the differentiation and maintenance of terminally fated effector CD8 T cells during infection. BRD4 bound diverse regulatory regions critical to effector T cell differentiation and controlled transcriptional activity of terminal effector-specific super-enhancers in vivo.

Physiological expression and function of the MDR1 transporter in cytotoxic T lymphocytes.

Multidrug resistance-1 (MDR1) acts as a chemotherapeutic drug efflux pump in tumor cells, although its physiological functions remain enigmatic. Using a recently developed MDR1-knockin reporter allele (Abcb1aAME), we found that constitutive MDR1 expression among hematopoietic cells was observed in cytolytic lymphocytes-including CD8+ cytotoxic T lymphocytes (CTLs) and natural killer cells-and regulated by Runt-related (Runx) transcription factors. Whereas MDR1 was dispensable for naive CD8+ T cell development, it was required for both the normal accumulation of effector CTLs following acute viral infection and the protective function of memory CTLs following challenge with an intracellular bacterium.

The Transcription Factor Runx3 Establishes Chromatin Accessibility of cis-Regulatory Landscapes that Drive Memory Cytotoxic T Lymphocyte Formation.

T cell receptor (TCR) stimulation of naive CD8 T cells initiates reprogramming of cis-regulatory landscapes that specify effector and memory cytotoxic T lymphocyte (CTL) differentiation. We mapped regions of hyper-accessible chromatin in naive cells during TCR stimulation and discovered that the transcription factor (TF) Runx3 promoted accessibility to memory CTL-specific cis-regulatory regions before the first cell division and was essential for memory CTL differentiation. Runx3 was specifically required for accessibility to regions highly enriched with IRF, bZIP and Prdm1-like TF motifs, upregulation of TFs Irf4 and Blimp1, and activation of fundamental CTL attributes in early effector and memory precursor cells.

Erratum: Runx3 programs CD8 T cell residency in non-lymphoid tissues and tumours.

This corrects the article DOI: 10.1038/nature24993.

Runx3 programs CD8 T cell residency in non-lymphoid tissues and tumours.

Tissue-resident memory CD8 T (T) cells are found at common sites of pathogen exposure, where they elicit rapid and robust protective immune responses. However, the molecular signals that control T cell differentiation and homeostasis are not fully understood. Here we show that mouse T precursor cells represent a unique CD8 T cell subset that is distinct from the precursors of circulating memory cell populations at the levels of gene expression and chromatin accessibility.