title: Alkbh1 and Tzfp repress a non-repeat piRNA cluster in pachytene spermatocytes.
abstract: Piwi proteins and Piwi-interacting small RNAs (piRNAs) have known functions in transposon silencing in the male germline of fetal and newborn mice. Both are also present in adult testes; however, their function here remains a mystery. Here, we confirm that most piRNAs in meiotic spermatocytes originate from clusters in non-repeat intergenic regions of DNA. The regulation of these piRNA clusters, including the processing of the precursor transcripts into individual piRNAs, is accomplished through mostly unknown processes. We present a possible regulatory mechanism for one such cluster, named cluster 1082B, located on chromosome 7 in the mouse genome. The 1082B precursor transcript and its 788 unique piRNAs are repressed by the Alkbh1 dioxygenase and the testis-specific transcription repressor Tzfp. We observe a remarkable >1000-fold upregulation of individual piRNAs in pachytene spermatocytes isolated from Alkbh1- and Tzfp-deficient murine testes. Repression of cluster 1082B is further supported by the identification of a 10-bp Tzfp recognition sequence contained within the precursor transcript. Downregulation of LINE1 and IAP transcripts in the Alkbh1- and Tzfp-deficient mice leads us to propose a potential role for the 1082B-encoded piRNAs in transposon control.
authors.affiliation: Department of Microbiology, Centre for Molecular Biology and Neuroscience, Oslo University Hospital, Rikshospitalet, PO Box 4950, Nydalen, NO-0424 Oslo, Norway.
authors.forename: Line M
authors.initials: LM
authors.lastname: Nordstrand
authors.forename: Kari
authors.initials: K
authors.lastname: Furu
authors.forename: Jonas
authors.initials: J
authors.lastname: Paulsen
authors.forename: Torbjørn
authors.initials: T
authors.lastname: Rognes
authors.forename: Arne
authors.initials: A
authors.lastname: Klungland
mesh_terms: D000071498:AlkB Homolog 1, Histone H2a Dioxygenase; D000818:Animals; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000235:genetics / Q000502:physiology*; D015536:Down-Regulation; D005786:Gene Expression Regulation; D007426:Genes, Intracisternal A-Particle; D020084:Long Interspersed Nucleotide Elements; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D009154:Mutation; D049471:Pachytene Stage / Q000235:genetics*; D012322:RNA Precursors / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D013090:Spermatocytes / Q000378:metabolism*; D013737:Testis / Q000378:metabolism
chemical_list: D012322:RNA Precursors; D034741:RNA, Small Interfering; D012097:Repressor Proteins; C406863:Rog protein, mouse; D000071498:AlkB Homolog 1, Histone H2a Dioxygenase; C529511:Alkbh1 protein, mouse; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase