biostudies-literaturePalacios VNIA NIH HHSNational Institutes of HealthNIGMS NIH HHSjcs258391https://www.ebi.ac.uk/biostudies/studies/S-EPMC8077489biostudies-literatureUnknown134(7)Germ cells undergo distinct nuclear processes as they differentiate into gametes. Although these events must be coordinated to ensure proper maturation, the stage-specific transport of proteins in and out of germ cell nuclei remains incompletely understood. Our efforts to genetically characterize Drosophila genes that exhibit enriched expression in germ cells led to the finding that loss of the highly conserved Importin β/karyopherin family member Importin-9 (Ipo9, herein referring to Ranbp9) results in female and male sterility. Immunofluorescence and fluorescent in situ hybridization revealed that Ipo9KO mutants display chromosome condensation and segregation defects during meiosis. In addition, Ipo9KO mutant males form abnormally structured sperm and fail to properly exchange histones fJournal of cell scienceImportin-9 regulates chromosome segregation and packaging in Drosophila germ cells.PMC8077489R01 AG047318R01 GM116885R01 GM125812R01GM116885 R01GM125812 R01AG047318Buszczak MTootle TLKimble GCPalacios VfalseImportin-9 regulates chromosome segregation and packaging in Drosophila germ cells.Germ cells undergo distinct nuclear processes as they differentiate into gametes. Although these events must be coordinated to ensure proper maturation, the stage-specific transport of proteins in and out of germ cell nuclei remains incompletely understood. Our efforts to genetically characterize Drosophila genes that exhibit enriched expression in germ cells led to the finding that loss of the highly conserved Importin β/karyopherin family member Importin-9 (Ipo9, herein referring to Ranbp9) results in female and male sterility. Immunofluorescence and fluorescent in situ hybridization revealed that Ipo9KO mutants display chromosome condensation and segregation defects during meiosis. In addition, Ipo9KO mutant males form abnormally structured sperm and fail to properly exchange histones f2021-01-01T00:00:00Z2021 Apr2025-04-29T11:29:34.716Z2025-04-06T19:55:14.467ZS-EPMC80774893363274410.1242/jcs.258391