title: Headcase promotes cell survival and niche maintenance in the Drosophila testis.
abstract: At the apical tip of the Drosophila testis, germline and somatic stem cells surround a cluster of somatic cells called the hub. Hub cells produce a self-renewal factor, Unpaired (Upd), that activates the JAK-STAT pathway in adjacent stem cells to regulate stem cell behavior. Therefore, apical hub cells are a critical component of the stem cell niche in the testis. In the course of a screen to identify factors involved in regulating hub maintenance, we identified headcase (hdc). Hub cells depleted for hdc undergo programmed cell death, suggesting that anti-apoptotic pathways play an important role in maintenance of the niche. Using hdc as paradigm, we describe here the first comprehensive analysis on the effects of a progressive niche reduction on the testis stem cell pool. Surprisingly, single hub cells remain capable of supporting numerous stem cells, indicating that although the size and number of niche support cells influence stem cell maintenance, the testis stem cell niche appears to be remarkably robust in the its ability to support stem cells after severe damage.
authors.affiliation: Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, United States of America.
authors.forename: Luís Pedro F
authors.initials: LP
authors.lastname: Resende
authors.forename: Monica
authors.initials: M
authors.lastname: Boyle
authors.forename: Darrell
authors.initials: D
authors.lastname: Tran
authors.forename: Thomas
authors.initials: T
authors.lastname: Fellner
authors.forename: D Leanne
authors.initials: DL
authors.lastname: Jones
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D002470:Cell Survival / Q000235:genetics; D004330:Drosophila / Q000235:genetics* / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism*; D008297:Male; D034622:RNA Interference; D055153:Stem Cell Niche / Q000502:physiology*; D013234:Stem Cells / Q000378:metabolism; D013737:Testis / Q000378:metabolism*; D059467:Transcriptome
chemical_list: D029721:Drosophila Proteins; C098014:Hdc protein, Drosophila