98%
921
2 minutes
20
During gene transcription, RNA polymerase II (RNA Pol II) passes nucleosomes with the help of various elongation factors. Here, we show that RNA Pol II achieves efficient nucleosome passage when the human elongation factors DSIF, PAF1 complex (PAF), RTF1, SPT6, and TFIIS are present. The cryo-EM structure of an intermediate of the nucleosome passage shows a partially unraveled hexasome that lacks the proximal H2A-H2B dimer and interacts with the RNA Pol II jaw, DSIF, and the CTR9trestle helix. RNA Pol II adopts a backtracked state with the RNA 3' end dislodged from the active site and bound in the RNA Pol II pore. Additional structures and biochemical data show that human TFIIS enters the RNA Pol II pore and stimulates the cleavage of the backtracked RNA and nucleosome passage.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.molcel.2022.06.027 | DOI Listing |
Proc Natl Acad Sci U S A
September 2025
HHMI and The Rockefeller University, New York, NY 10065.
Replication of cellular chromosomes requires a primase to generate short RNA primers to initiate genomic replication. While bacterial and archaeal primase generate short RNA primers, the eukaryotic primase, Polα-primase, contains both RNA primase and DNA polymerase (Pol) subunits that function together to form a >20 base hybrid RNA-DNA primer. Interestingly, the DNA Pol1 subunit of Polα lacks a 3'-5' proofreading exonuclease, contrary to the high-fidelity normally associated with DNA replication.
View Article and Find Full Text PDFAm J Hum Genet
September 2025
Department of Clinical Genetics, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, Rotterdam 3000 CA, the Netherlands.
Microtubule-actin cross-linking factor 1 (MACF1) is a large protein of the spectraplakin family, which is essential for brain development. MACF1 interacts with microtubules through the growth arrest-specific 2 (Gas2)-related (GAR) domain. Heterozygous MACF1 missense variants affecting the zinc-binding residues in this domain result in a distinctive cortical and brain stem malformation.
View Article and Find Full Text PDFBiochem J
September 2025
Cancer Research UK Scotland Institute, Glasgow, G61 1BD, U.K.
RNA cap formation on RNA polymerase II transcripts is regulated by cellular signalling pathways during development and differentiation, adaptive and innate immune responses, during the cell cycle and in response to oncogene deregulation. Here, we discuss how the RNA cap methyltransferase, RNA guanine-7 methyltransferase (RNMT), functions to complete the 7-methyl-guanosine or m7G cap. The mechanisms by which RNMT is regulated by signalling pathways, co-factors and other enzymes are explored.
View Article and Find Full Text PDFNAR Genom Bioinform
September 2025
Department of Internal Medicine, Nephrology Division, University of Michigan, Ann Arbor 48109 MI, United States.
The dynamics of transcriptional elongation influence many biological activities, such as RNA splicing, polyadenylation, and nuclear export. To quantify the elongation rate, a typical method is to treat cells with drugs that inhibit RNA polymerase II (Pol II) from entering the gene body and then track Pol II using Pro-seq or Gro-seq. However, the downstream data analysis is challenged by the problem of identifying the transition point between the gene regions inhibited by the drug and not, which is necessary to calculate the transcription rate.
View Article and Find Full Text PDFHIV-1 particle assembly depends critically on multiple proteolytic cleavages of viral polyproteins by the viral protease, PR. PR is translated as part of the Gag-Pro-Pol polyprotein, which undergoes autoproteolysis to liberate active, dimeric PR during virus particle maturation. Gag-Pro-Pol is produced via an infrequent -1 frameshifting event in ribosomes translating full length genomic RNA as Gag mRNA.
View Article and Find Full Text PDF