RBBP6 activates the pre-mRNA 3′-end processing machinery in humans

3′-end processing of most human mRNAs is carried out by the cleavage and polyadenylation specificity factor (CPSF; CPF in yeast). Endonucleolytic cleavage of the nascent pre-mRNA defines the 3′-end of the mature transcript, which is important for mRNA localization, translation and stability. Cleavage must therefore be tightly regulated. Here, we reconstitute specific and efficient 3′-endonuclease activity of human CPSF with purified proteins. This requires the seven-subunit CPSF as well as three additional protein factors: cleavage stimulatory factor (CStF), cleavage factor IIm (CFIIm) and, importantly, the multi-domain protein RBBP6. Unlike its yeast homologue Mpe1, which is a stable subunit of CPF, RBBP6 does not copurify with CPSF and is recruited in an RNA-dependent manner. Sequence and mutational analyses suggest that RBBP6 interacts with the WDR33 and CPSF73 subunits of CPSF. Thus, it is likely that the role of RBBP6 is conserved from yeast to human. Overall, our data are consistent with CPSF endonuclease activation and site-specific pre-mRNA cleavage being highly controlled to maintain fidelity in RNA processing.

Elevation of BSF-2 Level in Serum of Patients with Hepatitis B Virus

Background: Hepatitis B is the main infection of the injured liver for humans. Inflammation of the liver is caused by hepatitis viruses may lead to cirrhosis and hepatocellular carcinoma. The B-cell stimulatory factor 2 (BSF-2) is one of the cytokines that affect the regulation and differentiation of the human immune response. Objective: this report aims to estimate the BSF-2, GPT, and GOT levels in patients’ serum with different stages of hepatitis B compared with healthy control. Methods: This study assessed 52 patients presumably with acute and chronic cases who have HBsAg positive. BSF-2 was detected using ELISA assay. Biochemical parameters were determined using kits of an automated analyzer. SPSS version-16 software was used for statistical analysis. Results: Acute hepatitis B patients had shown elevation in BSF-2 level more than of chronic hepatitis B. GPT and GOT levels elevated in the acute hepatitis group more than of the chronic hepatitis group. We reported a significant value between BSF-2, GOT, and GPT levels. We didn’t score an association between patient’s age and cases groups of hepatitis. Conclusion: our data confirmed increasing of BSF-2 levels with the increase of GOT level more than GPT level with acute hepatitis B. BSF-2, GPT and GOT levels are varied in different courses of acute and chronic HBV. We surmised that the elevation of BSF-2 levels designates liver injury of patients with acute HBV.

RNA polymerase II CTD S2P is dispensable for embryogenesis but mediates exit from developmental diapause in C. elegans

Serine 2 phosphorylation (S2P) within the CTD of RNA polymerase II is considered a Cdk9/Cdk12-dependent mark required for 3′-end processing. However, the relevance of CTD S2P in metazoan development is unknown. We show that cdk-12 lesions or a full-length CTD S2A substitution results in an identical phenotype in Caenorhabditis elegans. Embryogenesis occurs in the complete absence of S2P, but the hatched larvae arrest development, mimicking the diapause induced when hatching occurs in the absence of food. Genome-wide analyses indicate that when CTD S2P is inhibited, only a subset of growth-related genes is not properly expressed. These genes correspond to SL2 trans-spliced mRNAs located in position 2 and over within operons. We show that CDK-12 is required for maximal occupancy of cleavage stimulatory factor necessary for SL2 trans-splicing. We propose that CTD S2P functions as a gene-specific signaling mark ensuring the nutritional control of the C. elegans developmental program.

A Novel Nomenclature for Repeat Motifs in the Thymidylate Synthase Enhancer Region and Its Relevance for Pharmacogenetic Studies

Inhibition of thymidylate synthase (TS) is the primary mode of action for 5-fluorouracil (5FU) chemotherapy. TS expression is modulated by a variable number of tandem repeats in the TS enhancer region (TSER) located upstream of the TS gene (TYMS). Variability in the TSER has been suggested to contribute to 5FU-induced adverse events. However, the precise genetic associations remain largely undefined due to high polymorphism and ambiguity in defining genotypes. To assess toxicity associations, we sequenced the TSER in 629 cancer patients treated with 5FU. Of the 13 alleles identified, few could be unambiguously named using current TSER-nomenclature. We devised a concise and unambiguous systematic naming approach for TSER-alleles that encompasses all known variants. After applying this comprehensive naming system to our data, we demonstrated that the number of upstream stimulatory factor (USF1-)binding sites in the TSER was significantly associated with gastrointestinal toxicity in 5FU treatment.

Molecular Docking, ADME Analysis, and Estimation of MM/GBSA Binding-Free Energies of Coumarin Derivatives as Potential Inhibitors of SARS CoV-2 Receptors

Coronavirus Disease (COVID-19) is recently declared pandemic (WHO) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Currently, there is no specific drug for the therapy of COVID-19. In the present study, in silico study have been done to find out possible inhibitors of SARS CoV-2. Coumarin derivatives with 2755 compounds were virtually screen against methyltransferase-stimulatory factor complex of NSP16 and NSP10, NSP15 Endoribonuclease, ADP ribose phosphatase (ADRP)of NSP3 and protease enzymes of SARS CoV-2. Docked top five compounds showed good docking scores and free energy of binding with the respective receptors. ADME/T analysis of docked compound shows the docked ligands are showing drug-likeness properties.