Live-imaging of single stem cells within their niche reveals that a U3snoRNP component segregates asymmetrically and is required for self-renewal in Drosophila.
Stem cells generate self-renewing and differentiating progeny over many rounds of asymmetric divisions. How stem cell growth rate and size are maintained over time remains unknown. We isolated mutations in a Drosophila melanogaster gene, wicked (wcd), which induce premature differentiation of germline stem cells (GSCs). Wcd is a member of the U3 snoRNP complex required for pre-ribosomal RNA maturation. This general function of Wcd contrasts with its specific requirement for GSC self-renewal. However, live imaging of GSCs within their niche revealed a pool of Wcd-forming particles that segregate asymmetrically into the GSCs on mitosis, independently of the Dpp signal sent by the niche. A fraction of Wcd also segregated asymmetrically in dividing larval neural stem cells (NSCs). In the absence of Wcd, NSCs became smaller and produced fewer neurons. Our results show that regulation of ribosome synthesis is a crucial parameter for stem cell maintenance and function.
Institut Jacques Monod, CNRS, Universités Paris 6 et 7, 2, place Jussieu, F-75251 Paris, Cedex 05, France.
Pierre
P
Fichelson
Clara
C
Moch
Kenzo
K
Ivanovitch
Charlotte
C
Martin
Clara M
CM
Sidor
Jean-Antoine
JA
Lepesant
Yohanns
Y
Bellaiche
Jean-René
JR
Huynh
D000818:Animals; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology* / Q000196:embryology* / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000502:physiology; D009865:Oocytes / Q000166:cytology / Q000502:physiology; D034622:RNA Interference; D012322:RNA Precursors / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020718:Ribonucleoproteins, Small Nucleolar / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D013234:Stem Cells / Q000166:cytology / Q000502:physiology
D029721:Drosophila Proteins; D012322:RNA Precursors; D011993:Recombinant Fusion Proteins; D020718:Ribonucleoproteins, Small Nucleolar; C064196:dpp protein, Drosophila; C117377:ribonucleoprotein, U3 small nucleolar