Mouse MAELSTROM: the link between meiotic silencing of unsynapsed chromatin and microRNA pathway?
Meiotic silencing of unsynapsed chromatin (MSUC) is a key mechanism in spermatogenesis and a model system to study the dynamics of gene silencing. Here we show that MAEL, the ortholog of Drosophila's high mobility group box protein Maelstrom, is associated not only with the silenced XY body, but also with unsynapsed autosomes. Characterization of MAEL revealed that it interacts directly with the chromatin remodeler SNF5/INI1 and chromatin-associated protein SIN3B, which we also find localized to the XY body. This is the first time that a chromatin remodeler has been shown to associate with whole chromosomes. In addition, we show that MAEL is a component of the mouse meiotic nuage and its haploid cell counterpart, the chromatoid body. This is a site of accumulation of RNA and RNA processing enzymes, including proteins involved in the microRNA (miRNA) pathway. Furthermore, in the nuage, MAEL is present in a complex with germ cell specific MVH, an RNA helicase and Argonaute family members, MILI and MIWI. The presence of MAEL in these critical compartments of male germ cells and its interactions provide a link suggesting the involvement of the miRNA pathway in MSUC.
Costa
Yael
Y
MRC Human Genetics Unit, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK.
Speed
Robert M
RM
Gautier
Philippe
P
Semple
Colin A
CA
Maratou
Klio
K
Turner
James M A
JM
Cooke
Howard J
HJ
D000818:Animals; D002843:Chromatin / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly; D002868:Chromosomal Proteins, Non-Histone; D023902:Chromosome Pairing / Q000235:genetics*; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D020868:Gene Silencing; D008297:Male; D008540:Meiosis / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000378:metabolism*; D008957:Models, Genetic; D012097:Repressor Proteins / Q000378:metabolism; D000071796:SMARCB1 Protein; D017386:Sequence Homology, Amino Acid; D012728:Sex Chromatin / Q000378:metabolism; D013091:Spermatogenesis / Q000502:physiology; D014157:Transcription Factors / Q000378:metabolism
D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D035683:MicroRNAs; D012097:Repressor Proteins; D000071796:SMARCB1 Protein; C115812:Sin3b protein, mouse; C513265:Smarcb1 protein, mouse; D014157:Transcription Factors; C109767:mael protein, Drosophila