Dgcr8 and Dicer are essential for sex chromosome integrity during meiosis in males.
Small RNAs play crucial roles in regulating gene expression during mammalian meiosis. To investigate the function of microRNAs (miRNAs) and small interfering RNAs (siRNAs) during meiosis in males, we generated germ-cell-specific conditional deletions of Dgcr8 and Dicer in mice. Analysis of spermatocytes from both conditional knockout lines revealed that there were frequent chromosomal fusions during meiosis, always involving one or both sex chromosomes. RNA sequencing indicates upregulation of Atm in spermatocytes from miRNA-deficient mice, and immunofluorescence imaging demonstrates an increased abundance of activated ATM kinase and mislocalization of phosphorylated MDC1, an ATM phosphorylation substrate. The Atm 3'UTR contains many potential microRNA target sites, and, notably, target sites for several miRNAs depleted in both conditional knockout mice were highly effective at promoting repression. RNF8, a telomere-associated protein whose localization is controlled by the MDC1-ATM kinase cascade, normally associates with the sex chromosomes during pachytene, but in both conditional knockouts redistributed to the autosomes. Taken together, these results suggest that Atm dysregulation in microRNA-deficient germ lines contributes to the redistribution of proteins involved in chromosomal stability from the sex chromosomes to the autosomes, resulting in sex chromosome fusions during meiotic prophase I.
Departments of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA.
Andrew J
AJ
Modzelewski
Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
Stephanie
S
Hilz
Departments of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA.
Elizabeth A
EA
Crate
Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
Caterina T H
CT
Schweidenback
Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
Elizabeth A
EA
Fogarty
Departments of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
Jennifer K
JK
Grenier
Unidad de Investigacion, Hospital Universitario de Canarias, Ofra s/n, La Cuesta, La Laguna, Tenerife 38320, Spain.
Raimundo
R
Freire
Departments of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA paula.cohen@cornell.edu agrimson@cornell.edu.
Paula E
PE
Cohen
Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA paula.cohen@cornell.edu agrimson@cornell.edu.
Andrew
A
Grimson
D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D053487:DEAD-box RNA Helicases / Q000502:physiology*; D005260:Female; D008297:Male; D008540:Meiosis / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D035683:MicroRNAs / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D016601:RNA-Binding Proteins / Q000502:physiology*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D043244:Ribonuclease III / Q000502:physiology*; D012730:Sex Chromosomes / Q000502:physiology*; D013090:Spermatocytes / Q000166:cytology / Q000502:physiology*
C474044:Dgcr8 protein, mouse; D035683:MicroRNAs; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D064007:Ataxia Telangiectasia Mutated Proteins; C509781:Dicer1 protein, mouse; D043244:Ribonuclease III; D053487:DEAD-box RNA Helicases
Dgcr8; Dicer; Dicer1; Germ line; Meiosis; MicroRNA; Sex body; Sex chromosomes; Telomere