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J Cell Sci. 2015 Jun 15;128(12):2314-27. doi: 10.1242/jcs.167148. Epub 2015 May 1.

Dgcr8 and Dicer are essential for sex chromosome integrity during meiosis in males.

Author information

1
Departments of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA.
2
Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
3
Departments of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
4
Unidad de Investigacion, Hospital Universitario de Canarias, Ofra s/n, La Cuesta, La Laguna, Tenerife 38320, Spain.
5
Departments of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA paula.cohen@cornell.edu agrimson@cornell.edu.
6
Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA paula.cohen@cornell.edu agrimson@cornell.edu.

Abstract

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.

KEYWORDS:

Dgcr8; Dicer; Dicer1; Germ line; Meiosis; MicroRNA; Sex body; Sex chromosomes; Telomere

PMID:
25934699
PMCID:
PMC4487015
DOI:
10.1242/jcs.167148
[Indexed for MEDLINE]
Free PMC Article

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