Título:	Chromatin structural changes around satellite repeats on the female sex chromosome in Schistosoma mansoni and their possible role in sex chromosome emergence.
Autoria:	LEPESANT, J. M. J. COSSEAU, C. BOISSIER, J. FREITAG, M. PORTELA, J. CLIMENT, D. PERRIN, C. ZERLOTINI, A. GRUNAU, C.
Afiliação:	JULIE M. J. LEPESANT, Université de Perpignan Via Domitia; CÉLINE COSSEAU, Université de Perpignan Via Domitia; JÉROME BOISSIER, Université de Perpignan Via Domitia; MICHAEL FREITAG, Oregon State University; JULIEN PORTELA, Université de Perpignan Via Domitia; DÉBORAH CLIMENT, Université de Perpignan Via Domitia; CÉCILE PERRIN, Université de Perpignan Via Domitia; ADHEMAR ZERLOTINI NETO, CNPTIA; CHRISTOPH GRUNAU, Université de Perpignan Via Domitia.
Ano de publicação:	2012
Referência:	Genome Biology, v. 13, 2012.
Páginas:	15 p.
Conteúdo:	Background: In the leuphotrochozoan parasitic platyhelminth Schistosoma mansoni, male individuals are homogametic (ZZ) whereas females are heterogametic (ZW). To elucidate the mechanisms that led to the emergence of sex chromosomes, we compared the genomic sequence and the chromatin structure of male and female individuals. As for many eukaryotes, the lower estimate for the repeat content is 40%, with an unknown proportion of domesticated repeats. We used massive sequencing to de novo assemble all repeats, and identify unambiguously Z-specific, W-specific and pseudoautosomal regions of the S. mansoni sex chromosomes. Results: We show that 70 to 90% of S. mansoni W and Z are pseudoautosomal. No female-specific gene could be identified. Instead, the W-specific region is composed almost entirely of 36 satellite repeat families, of which 33 were previously unknown. Transcription and chromatin status of female-specific repeats are stage-specific: for those repeats that are transcribed, transcription is restricted to the larval stages lacking sexual dimorphism. In contrast, in the sexually dimorphic adult stage of the life cycle, no transcription occurs. In addition, the euchromatic character of histone modifications around the W-specific repeats decreases during the life cycle. Recombination repression occurs in this region even if homologous sequences are present on both the Z and W chromosomes. Conclusion: Our study provides for the first time evidence for the hypothesis that, at least in organisms with a ZW type of sex chromosomes, repeat-induced chromatin structure changes could indeed be the initial event in sex chromosome emergence.
NAL Thesaurus:	Schistosoma
Digital Object Identifier:	10.1186/gb-2012-13-2-r14
Tipo do material:	Artigo de periódico
Acesso:	openAccess
Aparece nas coleções:	Artigo em periódico indexado (CNPTIA)