Over the past 10 years, the study of histone acetyltransferases (HATs) has advanced significantly, and a number of HATs have been isolated from various organisms. It emerged that HATs are highly diverse and generally contain multiple subunits. The functions of the catalytic subunit depend largely on the context of the other subunits in the complex. We are just beginning to understand the specialized roles of HAT complexes in chromosome decondensation, DNA-damage repair and the modification of non-histone substrates, as well as their role in the broader epigenetic landscape, including the role of protein domains within HAT complexes and the dynamic interplay between HAT complexes and existing histone modifications.

ObjectiveDNA-based testing of pancreatic cyst fluid (PCF) is a useful adjunct to the evaluation of pancreatic cysts (PCs). Mutations in KRAS/GNAS are highly specific for intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs), while TP53/PIK3CA/PTEN alterations are associated with advanced neoplasia. A prospective study was performed to evaluate preoperative PCF DNA testing.DesignOver 43-months, 626 PCF specimens from 595 patients were obtained by endoscopic ultrasound (EUS)-fine needle aspiration and assessed by targeted next-generation sequencing (NGS). Molecular results were correlated with EUS findings, ancillary studies and follow-up. A separate cohort of 159 PCF specimens was also evaluated for KRAS/GNAS mutations by Sanger sequencing.ResultsKRAS/GNAS mutations were identified in 308 (49%) PCs, while alterations in TP53/PIK3CA/PTEN were present in 35 (6%) cases. Based on 102 (17%) patients with surgical follow-up, KRAS/GNAS mutations were detected in 56 (100%) IPMNs and 3 (30%) MCNs, and associated with 89% sensitivity and 100% specificity for a mucinous PC. In comparison, KRAS/GNAS mutations by Sanger sequencing had a 65% sensitivity and 100% specificity. By NGS, the combination of KRAS/GNAS mutations and alterations in TP53/PIK3CA/PTEN had an 89% sensitivity and 100% specificity for advanced neoplasia. Ductal dilatation, a mural nodule and malignant cytopathology had lower sensitivities (42%, 32% and 32%, respectively) and specificities (74%, 94% and 98%, respectively).ConclusionsIn contrast to Sanger sequencing, preoperative NGS of PCF for KRAS/GNAS mutations is highly sensitive for IPMNs and specific for mucinous PCs. In addition, the combination of TP53/PIK3CA/PTEN alterations is a useful preoperative marker for advanced neoplasia.

Nesprin-1K K is a spectrin repeat (SR)-containing, transmembrane protein of the inner nuclear membrane, and is highly expressed in muscle cells. A yeast two-hybrid screen for nesprin-1K K-interacting proteins showed that nesprin-1K K interacted with itself. Blot overlay experiments revealed that nesprin-1K K's third SR binds the ¢fth SR. The carboxy-terminal half of nesprin-1K K directly bound lamin A, a nuclear intermediate ¢lament protein. Biochemical analysis demonstrated that nesprin-1K K dimers bind directly to the nucleoplasmic domain of emerin, an inner nuclear membrane protein, with an a⁄nity of 4 nM. Binding was optimal for full nucleoplasmic dimers of nesprin-1K K, since nesprin fragments SR1-5 and SR5-7 bound emerin as monomers with a⁄nities of 53 nM and 250 mM, respectively. We propose that membrane-anchored nesprin-1K K antiparallel dimers interact with both emerin and lamin A to provide sca¡olding at the inner nuclear membrane. ß 2002 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.

A combinatorial depletion strategy is combined with biochemistry, quantitative proteomics and computational approaches to elucidate the structure of the SAGA/ADA complexes. The analysis reveals five connected functional modules capable of independent assembly.

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Nonstop, which has previously been shown to have homology to ubiquitin proteases, is required for proper termination of axons R1–R6 in the optic lobe of the developing Drosophila eye. Herein, we establish that Nonstop actually functions as an ubiquitin protease to control the levels of ubiquitinated histone H2B in flies. We further establish that Nonstop is the functional homolog of yeast Ubp8, and can substitute for Ubp8 function in yeast cells. In yeast, Ubp8 activity requires Sgf11. We show that in Drosophila, loss of Sgf11 function causes similar photoreceptor axon‐targeting defects as loss of Nonstop. Ubp8 and Sgf11 are components of the yeast SAGA complex, suggesting that Nonstop function might be mediated through the Drosophila SAGA complex. Indeed, we find that Nonstop does associate with SAGA components in flies, and mutants in other SAGA subunits display nonstop phenotypes, indicating that SAGA complex is required for accurate axon guidance in the optic lobe. Candidate genes regulated by SAGA that may be required for correct axon targeting were identified by microarray analysis of gene expression in SAGA mutants.

Spinocerebellar ataxia (SCA) is a physically devastating, genetically inherited disorder characterized by abnormal brain function that results in the progressive loss of the ability to coordinate movements. There are many types of SCAs as there are various gene mutations that can cause this disease. SCA types 1-3, 6-10, 12, and 17 result from a trinucleotide repeat expansion in the DNAcoding sequence. Intriguingly, recent work has demonstrated that increased trinucleotde expansions in the SCA7 gene result in defect in the function of the SAGA histone acetyltransferase complex. The SCA7 gene encodes a subunit of the SAGA complex. This subunit is conserved in yeast as the SGF73 gene. We demonstrate that Sgf73 is required to recruit the histone deubiquitination module into both SAGA and the related SliK(SALSA) complex, and to maintain levels of histone ubiquitination, which is necessary for regulation of transcription at a number of genes.

IMPORTANCE Factors contributing to underrepresentation of women in surgery are incompletely understood. Pro-male bias and stereotype threat appear to contribute to gender imbalance in surgery.OBJECTIVES To evaluate the association between pro-male gender bias and career engagement and the effect of stereotype threat on skill performance among trainees in academic surgery. DESIGN, SETTING, AND PARTICIPANTSA 2-phase study with a double-blind, randomized clinical trial component was conducted in 3 academic general surgery training programs. Residents were recruited between August 1 and August 15, 2018, and the study was completed at the end of that academic year. In phase 1, surveys administered 5 to 6 months apart investigated the association of gender bias with career engagement. In phase 2, residents were randomized 1:1 using permuted-block design stratified by site, training level, and gender to receive either a trigger of or protection against stereotype threat. Immediately after the interventions, residents completed the Fundamentals of Laparoscopic Surgery (FLS) assessment followed by a final survey. A total of 131 general surgery residents were recruited; of these 96 individuals with academic career interests met eligibility criteria; 86 residents completed phase 1. Eighty-five residents were randomized in phase 2, and 4 residents in each arm were lost to follow-up.INTERVENTION Residents read abstracts that either reported that women had worse laparoscopic skill performance than men (trigger of stereotype threat [A]) or had no difference in performance (protection against stereotype threat [B]). MAIN OUTCOMES AND MEASURESAssociation between perception of pro-male gender bias and career engagement survey scores (phase 1) and stereotype threat intervention and FLS scores (phase 2) were the outcomes. Intention-to-treat analysis was conducted.RESULTS Seventy-seven residents (38 women [49.4%]) completed both phases of the study. The association between pro-male gender bias and career engagement differed by gender (interaction coefficient, −1.19; 95% CI, −1.90 to −0.49; P = .02); higher perception of bias was associated with higher engagement among men (coefficient, 1.02; 95% CI, 0.19-2.24; P = .04), but no significant association was observed among women (coefficient, −0.25; 95% CI, −1.59 to 1.08; P = .50). There was no evidence of a difference in FLS score between interventions (mean [SD], A: 395 [150] vs B: 367 [157]; P = .51). The response to stereotype threat activation was similar in men and women (interaction coefficient, 15.1; 95% CI, −124.5 to 154.7; P = .39). The association between stereotype threat activation and FLS score differed by gender across levels of susceptibility to stereotype threat (interaction coefficient, −35.3; 95% CI, −47.0 to −23.6; P = .006). Higher susceptibility to stereotype threat was associated with lower FLS scores among women who received a stereotype threat trigger (coefficient, −43.4; 95% CI, −48.0 to −38.9; P = .001).CONCLUSIONS AND RELEVANCE Perception of pro-male bias and ...