No abstract

Chromatin-modifying complexes containing histone deacetylase (HDAC) activities play critical roles in the regulation of gene transcription in eukaryotes. These complexes are thought to lack intrinsic DNA-binding activity, but according to a well-established paradigm, they are recruited via protein–protein interactions by gene-specific transcription factors and posttranslational histone modifications to their sites of action on the genome. The mammalian Sin3L/Rpd3L complex, comprising more than a dozen different polypeptides, is an ancient HDAC complex found in diverse eukaryotes. The subunits of this complex harbor conserved domains and motifs of unknown structure and function. Here, we show that Sds3, a constitutively-associated subunit critical for the proper functioning of the Sin3L/Rpd3L complex, harbors a type of Tudor domain that we designate the capped Tudor domain. Unlike canonical Tudor domains that bind modified histones, the Sds3 capped Tudor domain binds to nucleic acids that can form higher-order structures such as G-quadruplexes and shares similarities with the knotted Tudor domain of the Esa1 histone acetyltransferase that was previously shown to bind single-stranded RNA. Our findings expand the range of macromolecules capable of recruiting the Sin3L/Rpd3L complex and draw attention to potentially new biological roles for this HDAC complex.

BackgroundSince its inception, research in the clinical high-risk (CHR) phase of psychosis has included identifying and exploring the impact of relevant socio-demographic factors. Employing a narrative review approach and highlighting work from the United States, sociocultural and contextual factors potentially affecting the screening, assessment, and service utilization of youth at CHR were reviewed from the current literature.ResultsExisting literature suggests that contextual factors impact the predictive performance of widely used psychosis-risk screening tools and may introduce systemic bias and challenges to differential diagnosis in clinical assessment. Factors reviewed include racialized identity, discrimination, neighborhood context, trauma, immigration status, gender identity, sexual orientation, and age. Furthermore, racialized identity and traumatic experiences appear related to symptom severity and service utilization among this population.ConclusionsCollectively, a growing body of research from the United States and beyond suggests that considering context in psychosis-risk assessment can provide a more accurate appraisal of the nature of risk for psychosis, render more accurate results improving the field's prediction of conversion to psychosis, and enhance our understanding of psychosis-risk trajectories. More work is needed in the U.S. and across the globe to uncover how structural racism and systemic biases impact screening, assessment, treatment, and clinical and functional outcomes for those at CHR.

Chromatin-modifying complexes containing histone deacetylase (HDAC) activities play critical roles in the regulation of gene transcription in eukaryotes. These complexes are thought to lack intrinsic DNA-binding activity, but according to a well-established paradigm, they are recruited via protein-protein interactions by gene-specific transcription factors and post-translational histone modifications to their sites of action on the genome. The mammalian Sin3L/Rpd3L complex, comprising more than a dozen different polypeptides, is an ancient HDAC complex found in diverse eukaryotes. The subunits of this complex harbor conserved domains and motifs of unknown structure and function. Here we show that Sds3, a constitutively associated subunit critical for the proper functioning of the complex, harbors a type of Tudor domain that we designate the capped Tudor domain (CTD). Unlike canonical Tudor domains that bind modified histones, the Sds3 CTD binds to nucleic acids that can form higher-order structures such as G-quadruplexes, and shares similarities with the knotted Tudor domain of the Esa1 histone acetyltransferase (HAT) that was previously shown to bind single-stranded RNA. Our findings expand the range of macromolecules capable of recruiting the Sin3L/Rpd3L complex and draws attention to potentially new roles for this HDAC complex in transcription biology.