Reprogramação epigenética das células germinativas de rato e sua associação com a expressão de retrotransposons e de genes de defesa do genoma
Data
2015-02-27
Autores
Tesser, Renato Borges 
Orientadores
Teixeira, Taiza Stumpp
Tipo
Tese de doutorado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
As celulas germinativas primordiais (CGP) derivam das celulas epiblasticas no inicio da vida embrionaria e migram ate as gonadas. Neste periodo, as CGP passam por reprogramacao epigenetica, durante a qual o DNA e globalmente desmetilado, alterando o padrao de expressao genica, incluindo a expressao dos retrotransposons. Nosso grupo observou que a expressao da proteina MVH, que e especifica para as células germinativas e parece estar relacionada com o controle da expressao de retrotransposons e das proteinas PIWIL em camundongos, ocorre mais cedo no rato do que em camundongos. Assim, o objetivo deste estudo e investigar o periodo de reprogramacao das CGP de rato e o controle da expressao dos retrotransposons em comparacao com as CGP de camundongos. Para isso, investigou-se a relacao entre a expressao das proteinas MVH, DAZL e PIWILs, a expressao dos genes de protecao do genoma (Piwil1, Piwil2, Piwil4, Tex19.1, Aszl1 e Mov101L) e a expressao dos retrotransposons Iap e Line-1 nas CGP e testiculos pos natais de rato. Investigou-se tambem se a expressao dos genes relacionados a protecao do genoma e controlada por metilacao. A presenca das proteinas MVH e DAZL foi observada nas CGP entre 13 e 15dpc, mas nao aos 12dpc. As proteinas PIWIL1 e PIWIL2 foram detectadas apenas na fase adulta, em celulas meioticas, coincidindo com a localizacao das proteinas DAZL e MVH, embora a expressao dos respectivos genes tenha sido observada nas CGP aos 15dpc. Foi observada expressao de PIWIL4 nas CGP dos 12 aos 15dpc. A expressão dos genes de protecao do genoma e dos retrotransposons Line-1 e Iap foi observada nas CGP aos 15dpc e em testiculo adulto. Os dados obtidos indicam que as proteínas MVH, DAZL e PIWIL4 estao presentes no desenvolvimento das CGP de rato e sua expressao, bem como o periodo de reprogramacao epigenetica, tem inicio mais cedo do que em camundongos, sugerindo que o controle da expressao dos retrotransposons nas CGP desses animais e diferente daquele observado em camundongos.
Primordial germ cells (PGC) arise from the epiblast cells in the beginning of embryonary period and migrate to the gonads. During this phase, PGC undergo epigenetic reprogramming, global DNA is demethylated, changing the pattern of genic expression, including retrotransposons expressions. Our group showed the expression of the MVH protein, which is germ cell specific and possible control the retrotransposons expression and PIWIL proteins in mice, occurring early than in mice. Based on this, the aim of this study is investigate the period of mouse PGC reprogramming and if the control of retrotransposons expression. It was investigated the relationship among the proteins expression MVH, DAZL and PIWILs, the expression of defence genes of genome (Piwil1, Piwil2, Piwil4, Tex19.1, Aszl1 and Mov101L) and the expression of retrotransposons IAP and Line1 in CGP and post natal rat testis. It was also investigated if the expression of the defence genes of the genome is controlled by methylation. The protein Piwil2 was only observed at 14 and 15dpc. The presence of the proteins MVH and DAZL was observed in PGC at 13 to 15dpc, but not in PGC at 12dpc. PIWIL1 and PIWIL2 proteins was detected only in adult phase, in meiotic cells, at the same localization as DAZL and MVH proteins, although the expression of respective genes have been observed in 15dpc PGC. It was observed the expression of PIWIL4 at 12 to 15dpc PGC. The expression pf genes defence of the genome and IAP and Line1 retrotransposons was observed at 15dpc PGC and in adult testis. The results obtained showed that the proteins MVH, DAZL and PIWIL4 are expressed in rat PGC and that their expression, as well epigenetic reprograming, occur earlier than in mouse PGC, indicating that the control of retrotransposon expression in rat PGC is different from mice.
Primordial germ cells (PGC) arise from the epiblast cells in the beginning of embryonary period and migrate to the gonads. During this phase, PGC undergo epigenetic reprogramming, global DNA is demethylated, changing the pattern of genic expression, including retrotransposons expressions. Our group showed the expression of the MVH protein, which is germ cell specific and possible control the retrotransposons expression and PIWIL proteins in mice, occurring early than in mice. Based on this, the aim of this study is investigate the period of mouse PGC reprogramming and if the control of retrotransposons expression. It was investigated the relationship among the proteins expression MVH, DAZL and PIWILs, the expression of defence genes of genome (Piwil1, Piwil2, Piwil4, Tex19.1, Aszl1 and Mov101L) and the expression of retrotransposons IAP and Line1 in CGP and post natal rat testis. It was also investigated if the expression of the defence genes of the genome is controlled by methylation. The protein Piwil2 was only observed at 14 and 15dpc. The presence of the proteins MVH and DAZL was observed in PGC at 13 to 15dpc, but not in PGC at 12dpc. PIWIL1 and PIWIL2 proteins was detected only in adult phase, in meiotic cells, at the same localization as DAZL and MVH proteins, although the expression of respective genes have been observed in 15dpc PGC. It was observed the expression of PIWIL4 at 12 to 15dpc PGC. The expression pf genes defence of the genome and IAP and Line1 retrotransposons was observed at 15dpc PGC and in adult testis. The results obtained showed that the proteins MVH, DAZL and PIWIL4 are expressed in rat PGC and that their expression, as well epigenetic reprograming, occur earlier than in mouse PGC, indicating that the control of retrotransposon expression in rat PGC is different from mice.
Descrição
Citação
TESSER, Renato Borges. Reprogramação epigenética das células germinativas de rato e sua associação com a expressão de retrotransposons e de genes de defesa do genoma. 2015. 70 f. Tese (Doutorado em Biologia Estrutural e Funcional) - Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, 2015.