TY - JOUR T1 - Dynamic Sex Chromosome Expression in Drosophila Male Germ Cells JF - bioRxiv DO - 10.1101/2020.03.23.000356 SP - 2020.03.23.000356 AU - Sharvani Mahadevaraju AU - Justin M. Fear AU - Miriam Akeju AU - Brian J. Galletta AU - Mara MLS. Pinheiro AU - Camila C. Avelino AU - Diogo C. Cabral-de-Mello AU - Katie Conlon AU - Stafania Dell’Orso AU - Zelalem Demere AU - Kush Mansuria AU - Carolina A. Mendonça AU - Octavio M. Palacios-Gimenez AU - Eli Ross AU - Max Savery AU - Kevin Yu AU - Harold E. Smith AU - Vittorio Sartorelli AU - Nasser M. Rusan AU - Maria D. Vibranovski AU - Erika Matunis AU - Brian Oliver Y1 - 2020/01/01 UR - http://biorxiv.org/content/early/2020/03/23/2020.03.23.000356.abstract N2 - Sex chromosome gene content and expression is unusual. In many organisms the X and Y chromosomes are inactivated in spermatocytes, possibly as a defense mechanism against insertions into unpaired chromatin. In addition to current sex chromosomes, Drosophila has a small gene-poor X-chromosome relic (4th) that re-acquired autosomal status. Using single cell RNA-Seq, we demonstrate that the single X and pair of 4th chromosomes are specifically inactivated in primary spermatocytes. In contrast, genes on the single Y chromosome become maximally active in primary spermatocytes. Reduced X steady-state transcript levels are due to failed activation of RNA-Polymerase-II by phosphorylation of Serine 2 and 5.One Sentence Summary Sex chromosome expression during spermatogenesis at the single cell level ER -