Benitez, B. | bioRxiv Science

bioRxiv2024

Hallmarks of glucocorticoid receptor condensates involvement in transcription regulation

Several proteins necessary for mRNA production concentrate in intranuclear condensates, which are proposed to affect transcriptional output. The glucocorticoid receptor (GR) is a ligand-activated transcription factor that regulates the expression of hundreds of genes relevant to many physiological and pathological processes. As with all members of the steroid receptor family, GR forms condensates of unknown function. Here, we examine whether GR condensates are involved in transcription regulation using Airyscan super-resolution microscopy and nano-antibodies targeting initiation and elongating states of RNA polymerase II (Pol2). We observed subpopulations of GR condensates colocalizing with initiating and, surprisingly, elongating Pol2 foci. The analysis of GR mutants with different transcriptional outputs suggests a correlation between condensate formation capability and transcription initiation. Moreover, the number of GR molecules within initiation and elongation condensates appears to be linked to transcriptional activity. Taken together, our data suggests an involvement of GR condensates in transcription initiation and elongation. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=141 SRC="FIGDIR/small/623561v1_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@969a77org.highwire.dtl.DTLVardef@176fcfborg.highwire.dtl.DTLVardef@dae13dorg.highwire.dtl.DTLVardef@1f96c3b_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗

bioRxiv2018

The MS4A gene cluster is a key regulator of soluble TREM2 and Alzheimer disease risk

Soluble triggering receptor expressed on myeloid cells 2 (sTREM2) levels in the cerebrospinal fluid (CSF) have been associated with Alzheimer disease (AD) status. TREM2 plays a critical role in microglial activation, survival, and phagocytosis; however, the pathophysiological role of sTREM2 in AD is not well understood. Understanding the role of sTREM2 in AD may help reveal biological mechanisms underlying AD and identify novel therapeutic targets. We performed a genome-wide association study (GWAS) to identify genetic modifiers of CSF sTREM2 levels. Common variants in the membrane-spanning 4-domains subfamily A (MS4A) gene region were associated with higher CSF sTREM2 levels (rs1582763; P = 1.15x10-15) and replicated in independent datasets. The variants associated with increased levels of sTREM2 are also associated with reduced AD risk and delayed age-at-onset. Rs1582763 influences expression of MS4A4A and MS4A6A in multiple tissues, suggesting that one or both of these genes are important for regulating sTREM2. MS4A genes encode transmembrane proteins that may play a role in intracellular protein trafficking in microglia. We used human macrophages to begin to test the relationship between MS4A4A and TREM2 and found that they co-localize intracellularly and that antibody-mediated targeting of MS4A4A reduces sTREM2. Thus, genetic, molecular, and cellular findings suggest that MS4A4A regulates sTREM2. These findings also provide a mechanistic explanation of the original GWAS signal in the MS4A locus for AD risk and indicate that TREM2 is involved in sporadic AD risk in general, not only in TREM2 risk-variant carriers.

genomics↗