The nuage mediates retrotransposon silencing in mouse primordial ovarian follicles.
Mobilization of endogenous retrotransposons can destabilize the genome, an imminent danger during epigenetic reprogramming of cells in the germline. The P-element-induced wimpy testis (PIWI)-interacting RNA (piRNA) pathway is known to silence retrotransposons in the mouse testes. Several piRNA pathway components localize to the unique, germline structure known as the nuage. In this study, we surveyed mouse ovaries and found, for the first time, transient appearance of nuage-like structures in oocytes of primordial follicles. Mouse vasa homolog (MVH), Piwi-like 2 (PIWIL2/MILI) and tudor domain-containing 9 (TDRD9) are present in these structures, whereas aggregates of germ cell protein with ankyrin repeats, sterile alpha motif and leucine zipper (GASZ) localize separately in the cytoplasm. Retrotransposons are silenced in primordial ovarian follicles, and de-repressed upon reduction of piRNA expression in Mvh, Mili or Gasz mutants. However, these null-mutant females, unlike their male counterparts, are fertile, uncoupling retrotransposon activation from sterility.
Institute of Medical Biology, A*STAR, 8A Biomedical Grove, Immunos, 138648 Singapore. aikhim.lim@imb.a-star.edu.sg
Ai Khim
AK
Lim
Chanchao
C
Lorthongpanich
Ting Gang
TG
Chew
Chin Wee Godwin
CW
Tan
Yan Ting
YT
Shue
Sathish
S
Balu
Natalia
N
Gounko
Satomi
S
Kuramochi-Miyagawa
Martin M
MM
Matzuk
Shinichiro
S
Chuma
Daniel M
DM
Messerschmidt
Davor
D
Solter
Barbara B
BB
Knowles
D000818:Animals; D022082:Cellular Structures / Q000378:metabolism* / Q000648:ultrastructure; D005260:Female; D005786:Gene Expression Regulation; D020868:Gene Silencing; D005854:Germ Cells / Q000378:metabolism; D007247:Infertility, Female / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation / Q000235:genetics; D009866:Oogenesis; D006080:Ovarian Follicle / Q000378:metabolism* / Q000648:ultrastructure; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D018626:Retroelements / Q000235:genetics*
D012333:RNA, Messenger; D034741:RNA, Small Interfering; D018626:Retroelements
Mouse; Nuage; Ovary; Primordial follicles; Retrotransposons; piRNAs