Nonsense-mutation-containing messenger ribonucleoprotein particles (mRNPs) transit through cytoplasmic foci called P-bodies before undergoing nonsense-mediated mRNA decay (NMD), a cytoplasmic mRNA surveillance mechanism. This study shows that the cytoskeleton modulates transport of nonsense-mutation-containing mRNPs to and from P-bodies. Impairing the integrity of cytoskeleton causes inhibition of NMD. The cytoskeleton thus plays a crucial role in NMD. Interestingly, disruption of actin filaments results in both inhibition of NMD and activation of premature termination codon (PTC) readthrough, while disruption of microtubules causes only NMD inhibition. Activation of PTC readthrough occurs concomitantly with the appearance of cytoplasmic foci containing UPF proteins and mRNAs with nonsense mutations but lacking the P-body marker DCP1a. These findings demonstrate that in human cells, PTC readthrough occurs in novel 'readthrough bodies' and requires the presence of UPF proteins.
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http://dx.doi.org/10.1242/jcs.198176 | DOI Listing |
Sci Adv
January 2025
MOE Key Laboratory for Cellular Dynamics and Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230027, China.
Microtubule assembly takes place at the centrosome and noncentrosomal microtubule-organizing centers (MTOCs). However, the mechanisms controlling the activity of noncentrosomal MTOCs are poorly understood. Here, using the fission yeast as a model organism, we demonstrate that the kinesin-14 motor Klp2 interacts with the J-domain Hsp70/Ssa1 cochaperone Rsp1, an inhibitory factor of microtubule assembly, and that Klp2 is required for the proper localization of Rsp1 to microtubules.
View Article and Find Full Text PDFDev Cell
December 2024
Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei 230027, China. Electronic address:
Germ granules, or nuage, are RNA-rich condensates that are often docked on the cytoplasmic surface of germline nuclei. C. elegans perinuclear germ granules are composed of multiple subcompartments, including P granules, Mutator foci, Z granules, SIMR foci, P -bodies, and E granules.
View Article and Find Full Text PDFInt J Gynecol Pathol
December 2024
Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine.
Transitional cell metaplasia (TCM) resembling benign urothelium is commonly seen around the distal fallopian tube and/or neighboring mesothelial surface; however, its histogenesis remains largely unknown. We observed the emergence of a cytokeratin (CK) 17-positive reserve cell layer in early TCM foci beneath the tubal epithelium, leading us to hypothesize that TCM could be derived from reserve cells. To elucidate the histogenetic process of TCM, we analyzed the histomorphologic features and immunoprofiles for CK17, CK5/6, p63, GATA-3, estrogen receptor (ER), and androgen receptor (AR) in TCM foci arising in the tubal epithelium (31 foci) and pelvic mesothelium (35 foci).
View Article and Find Full Text PDFBiochemistry (Mosc)
November 2024
N. N. Petrov National Medical Research Center of Oncology, St. Petersburg, 197758, Russia.
Life Sci Alliance
February 2025
Department of Biochemistry, University of Toronto, Toronto, Canada
In humans, misprocessed mRNAs containing intact 5' Splice Site (5'SS) motifs are nuclear retained and targeted for decay by ZFC3H1, a component of the Poly(A) Exosome Targeting complex, and U1-70K, a component of the U1 snRNP. In , the ZFC3H1 homolog, Red1, binds to the YTH domain-containing protein Mmi1 and targets certain RNA transcripts to nuclear foci for nuclear retention and decay. Here we show that YTHDC1 and YTHDC2, two YTH domain-containing proteins that bind to -6-methyladenosine (m6A) modified RNAs, interact with ZFC3H1 and U1-70K, and are required for the nuclear retention of mRNAs with intact 5'SS motifs.
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