Acetylation-Dependent Recruitment of the FACT Complex and Its Role in Regulating Pol II Occupancy Genome-Wide in Saccharomyces cerevisiae.

Histone chaperones, chromatin remodelers, and histone modifying complexes play a critical role in alleviating the nucleosomal barrier for DNA-dependent processes. Here, we have examined the role of two highly conserved yeast (Saccharomyces cerevisiae) histone chaperones, facilitates chromatin transcription (FACT) and Spt6, in regulating transcription. We show that the H3 tail contributes to the recruitment of FACT to coding sequences in a manner dependent on acetylation. We found that deleting a H3 histone acetyltransferase Gcn5 or mutating lysines on the H3 tail impairs FACT recruitment at ADH1 and ARG1 genes. However, deleting the H4 tail or mutating the H4 lysines failed to dampen FACT occupancy in coding regions. Additionally, we show that FACT depletion reduces RNA polymerase II (Pol II) occupancy genome-wide. Spt6 depletion leads to a reduction in Pol II occupancy toward the 3'-end, in a manner dependent on the gene length. Severe transcription and histone-eviction defects were also observed in a strain that was impaired for Spt6 recruitment (spt6Δ202) and depleted of FACT. Importantly, the severity of the defect strongly correlated with wild-type Pol II occupancies at these genes, indicating critical roles for Spt6 and Spt16 in promoting high-level transcription. Collectively, our results show that both FACT and Spt6 are important for transcription globally and may participate during different stages of transcription.

Macrophage migration inhibitory factor is associated with vascular dysfunction in patients with end-stage renal disease.

BACKGROUND: Patients with end-stage renal disease (ESRD) show a high prevalence of cardiovascular disease with arterial stiffness, atherosclerosis and endothelial dysfunction, leading to increased morbidity and mortality. The cytokine macrophage migration inhibitory factor (MIF) exhibits proinflammatory and proatherogenic functions and has recently emerged as a major regulator of atherogenesis. Studies examining the relationship between circulating MIF levels and vascular dysfunction in this high-risk population do not exist. METHODS: In patients with ESRD (n = 39) and healthy controls (n = 16) we assessed endothelial function by flow-mediated dilation of the brachial artery and arterial stiffness (augmentation pressure, augmentation index and pulse pressure) using applanation tonometry. High-sensitive Troponin and subendocardial viability ratio were determined to assess myocardial injury. RESULTS: Patients with ESRD had impaired endothelial function and higher plasma MIF levels. MIF levels negatively correlated with endothelial function (r = -0.345, P = 0.031) and positively with arterial stiffness indices in patients with ESRD (pulse pressure r = -0.374, P = 0.019 and augmentation pressure r = -0.423, P = 0.025). In multivariate regression models besides age, gender, weight, and heart rate, MIF was an independent predictor for arterial stiffness. Impact on myocardial end-organ damage was reflected by correlation with high-sensitive Troponin I (r = 0.43, P = 0.009). CONCLUSION: Our findings show that high MIF plasma levels are associated with diminished endothelial function and arterial stiffness and are correlated with myocardial injury. Further studies are necessary to investigate whether modulation of MIF might have an impact on atherosclerotic disease in this high-risk population.