Mouse maelstrom, a component of nuage, is essential for spermatogenesis and transposon repression in meiosis.
Tight control of transposon activity is essential for the integrity of the germline. Recently, a germ-cell-specific organelle, nuage, was proposed to play a role in transposon repression. To test this hypothesis, we disrupted a murine homolog of a Drosophila nuage protein Maelstrom. Effects on male meiotic chromosome synapsis and derepression of transposable elements (TEs) were observed. In the adult Mael(-/-) testes, LINE-1 (L1) derepression occurred at the onset of meiosis. As a result, Mael(-/-) spermatocytes were flooded with L1 ribonucleoproteins (RNPs) that accumulated in large cytoplasmic enclaves and nuclei. Mael(-/-) spermatocytes with nuclear L1 RNPs exhibited massive DNA damage and severe chromosome asynapsis even in the absence of SPO11-generated meiotic double-strand breaks. This study demonstrates that MAEL, a nuage component, is indispensable for the silencing of TEs and identifies the initiation of meiosis as an important step in TE control in the male germline.
Soper
Sarah F C
SF
Biology Department, Johns Hopkins University, Baltimore, MD 21218, USA.
van der Heijden
Godfried W
GW
Hardiman
Tara C
TC
Goodheart
Mary
M
Martin
Sandra L
SL
de Boer
Peter
P
Bortvin
Alex
A
D000483:Alleles; D000818:Animals; D022003:Cell Nucleus Structures / Q000378:metabolism* / Q000648:ultrastructure; D023902:Chromosome Pairing; D033481:Chromosomes, Mammalian / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D019175:DNA Methylation; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004706:Endodeoxyribonucleases; D004950:Esterases / Q000378:metabolism; D018390:Gene Targeting; D008297:Male; D008540:Meiosis; D051379:Mice; D008810:Mice, Inbred C57BL; D016366:Open Reading Frames / Q000235:genetics; D021381:Protein Transport; D012261:Ribonucleoproteins / Q000378:metabolism; D012730:Sex Chromosomes / Q000378:metabolism; D013090:Spermatocytes / Q000166:cytology / Q000648:ultrastructure; D013091:Spermatogenesis; D013094:Spermatozoa / Q000166:cytology / Q000648:ultrastructure; D013737:Testis / Q000166:cytology / Q000648:ultrastructure; D014157:Transcription Factors / Q000378:metabolism*; D000099257:Meiotic Recombination Protein SPO11
D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; D004706:Endodeoxyribonucleases; D004950:Esterases; D012261:Ribonucleoproteins; D014157:Transcription Factors; D000099257:Meiotic Recombination Protein SPO11; C531147:maelstrom protein, mouse