In Drosophila ovarian somatic cells (OSCs), Piwi represses transposons transcriptionally to maintain genome integrity. Piwi nuclear localization requires the N terminus and PIWI-interacting RNA (piRNA) loading of Piwi. However, the underlying mechanism remains unknown. Here, we show that Importinα (Impα) plays a pivotal role in Piwi nuclear localization and that Piwi has a bipartite nuclear localization signal (NLS). Impα2 and Impα3 are highly expressed in OSCs, whereas Impα1 is the least expressed. Loss of Impα2 or Impα3 forces Piwi to be cytoplasmic, which is rectified by overexpression of any Impα members. Extension of Piwi-NLS with an additional Piwi-NLS leads Piwi to be imported to the nucleus in a piRNA-independent manner, whereas replacement of Piwi-NLS with SV40-NLS fails. Limited proteolysis analysis suggests that piRNA loading onto Piwi triggers conformational change, exposing the N terminus to the environment. These results suggest that Piwi autoregulates its nuclear localization by exposing the NLS to Impα upon piRNA loading.
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http://dx.doi.org/10.1016/j.celrep.2018.05.051 | DOI Listing |
J Gastrointest Cancer
January 2025
Department of Radiotherapy and Radiation Oncology, Jena University Hospital, 07747, Jena, Germany.
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January 2025
Department of Neurosurgery, Faculty of Medicine, Hokkaido University, Sapporo, Japan.
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View Article and Find Full Text PDFJ Plant Physiol
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Department of Life Science and Environmental Biochemistry, and Life and Industry Convergence Research Institute, Pusan National University, Miryang, 50463, Republic of Korea. Electronic address:
Pollen tubes are crucial for angiosperm plants, as they deliver sperm gametes for the essential process of double fertilization. Understanding the molecular mechanisms behind pollen tube germination and growth is critical; however, these processes remain partially elucidated in monocot cereal crops. Rapid Alkalinization Factor (RALF), a small peptide of about 5Â kDa, binds to the CrRLK1L receptor and plays a role in various plant physiological processes, including reproduction and tip growth.
View Article and Find Full Text PDFCell Death Differ
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School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong, 510006, China.
Clinical treatment options for triple-negative breast cancer (TNBC) are currently limited to chemotherapy because of a lack of effective therapeutic targets. Recent evidence suggests that long noncoding RNAs (lncRNAs) encode bioactive peptides or proteins, thereby playing noncanonical yet significant roles in regulating cellular processes. However, the potential of lncRNA-translated products in cancer progression remains largely unknown.
View Article and Find Full Text PDFJ Biol Chem
January 2025
Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, China. Electronic address:
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