title: Protein synthesis and degradation are essential to regulate germline stem cell homeostasis in Drosophila testes.
abstract: The homeostasis of self-renewal and differentiation in stem cells is controlled by intrinsic signals and their niche. We conducted a large-scale RNA interference (RNAi) screen in Drosophila testes and identified 221 genes required for germline stem cell (GSC) maintenance or differentiation. Knockdown of these genes in transit-amplifying spermatogonia and cyst cells further revealed various phenotypes. Complex analysis uncovered that many of the identified genes are involved in key steps of protein synthesis and degradation. A group of genes that are required for mRNA splicing and protein translation contributes to both GSC self-renewal and early germ cell differentiation. Loss of genes in the protein degradation pathway in cyst cells leads to testis tumors consisting of overproliferated germ cells. Importantly, in the Cullin 4-RING E3 ubiquitin ligase (CRL4) complex, we identified multiple proteins that are crucial to GSC self-renewal: pic/DDB1, a CRL4 linker protein, is not only required for GSC self-renewal in flies but also for maintenance of spermatogonial stem cells (SSCs) in mice.
authors.affiliation: Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China Department of Obstetrics and Gynecology, Affiliated Hospital of Jiangsu University, Jiangsu University, Zhenjiang 212013, China Department of Histology and Embryology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Yu
authors.affiliation: Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Lan
authors.affiliation: State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China Department of Obstetrics and Gynecology, Affiliated Hospital of Jiangsu University, Jiangsu University, Zhenjiang 212013, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Chen
authors.affiliation: Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Yu
authors.affiliation: Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China.
authors.forename: Yiwen
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China Department of Histology and Embryology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Yujuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China.
authors.forename: Lingna
authors.initials: L
authors.lastname: Xu
authors.affiliation: Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China.
authors.forename: Heng-Yu
authors.initials: HY
authors.lastname: Fan
authors.affiliation: Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China ctong@zju.edu.cn.
authors.forename: Chao
authors.identifier: 0000-0001-6521-5465
authors.initials: C
authors.lastname: Tong
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D000066673:Cell Self Renewal / Q000235:genetics / Q000502:physiology; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D012326:RNA Splicing / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism*; D013737:Testis / Q000166:cytology* / Q000378:metabolism*; D043743:Ubiquitin-Protein Ligase Complexes / Q000235:genetics / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D012333:RNA, Messenger; D043743:Ubiquitin-Protein Ligase Complexes; C568503:CRL4(Cdt2) protein, Drosophila
keywords: Differentiation; Drosophila; Germline stem cells; Self-renewal; Testis