359A Poster - 04. Stem cells, regeneration and tissue injury
Thursday April 07, 2:00 PM - 4:00 PM

Authors:
Sreesankar Easwaran; Denise Montell

Affiliation: University of California - Santa Barbara

Keywords:
b. germline stem cell; a. stress responses

A consequence of aging in many species including humans is reduced female fertility. Intriguingly, some species can preserve fertility longer under specific environmental conditions. For example, at low temperature and short day-length, Drosophila melanogaster can enter a dormant state called adult reproductive diapause. During this cold-induced quiescence, as in other stressful conditions, ovarian development arrests at the yolk uptake checkpoint. However, mechanisms underlying fertility preservation and post-diapause recovery are largely unknown. Here, we report the effects of cold-induced arrest and recovery on Drosophila ovarian development. We found that diapause affects all stages including germline stem cells (GSCs) and is distinct from other stress responses in causing more complete arrest yet preserving the potential for recovery. Further, GSCs incur DNA damage, activate p53 and the Chk2 checkpoint, and divide less during dormancy. Niche signaling is reduced yet germline precursor cells do not differentiate. Thus, GSCs adopt an atypical, suspended state connected to cystoblast daughters. Post-diapause recovery of niche signaling, resumption of GSC division, and dedifferentiation contribute to restoring GSCs. Mimicking one feature of the quiescent state, reduced juvenile hormone production, enhanced GSC longevity in non-diapausing flies. Thus, studies of adult reproductive diapause in Drosophila can provide approaches to GSC longevity enhancement.