Bateman, Jack R.Larschan, EricaD’Souza, RyanMarshall, Lauren S.Dempsey, KyleJohnson, Justine E.Mellone, Barbara G.Kuroda, Mitzi2013-03-262012Bateman, Jack R., Erica Larschan, Ryan D’Souza, Lauren S. Marshall, Kyle E. Dempsey, Justine E. Johnson, Barbara G. Mellone, and Mitzi I. Kuroda. 2012. A genome-wide screen identifies genes that affect somatic homolog pairing in drosophila. G3: Genes, Genomes, Genetics 2(7): 731-740.2160-1836http://nrs.harvard.edu/urn-3:HUL.InstRepos:10465036In Drosophila and other Dipterans, homologous chromosomes are in close contact in virtually all nuclei, a phenomenon known as somatic homolog pairing. Although homolog pairing has been recognized for over a century, relatively little is known about its regulation. We performed a genome-wide RNAi-based screen that monitored the X-specific localization of the male-specific lethal (MSL) complex, and we identified 59 candidate genes whose knockdown via RNAi causes a change in the pattern of MSL staining that is consistent with a disruption of X-chromosomal homolog pairing. Using DNA fluorescent in situ hybridization (FISH), we confirmed that knockdown of 17 of these genes has a dramatic effect on pairing of the 359 bp repeat at the base of the X. Furthermore, dsRNAs targeting Pr-set7, which encodes an H4K20 methyltransferase, cause a modest disruption in somatic homolog pairing. Consistent with our results in cultured cells, a classical mutation in one of the strongest candidate genes, pebble (pbl), causes a decrease in somatic homolog pairing in developing embryos. Interestingly, many of the genes identified by our screen have known roles in diverse cell-cycle events, suggesting an important link between somatic homolog pairing and the choreography of chromosomes during the cell cycle.en-USJournal Article2013-03-2610.1534/g3.112.002840