Association of the 5hmC epigentic mark with the retrotransposons IAP and LINE1 and Tet1 and TDG expression in rat primordial germ cells during the epigenetic reprogramming

• Grant number: 15/23171-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2016
• End date: November 30, 2016
• Field of knowledge: Biological Sciences - Morphology - Embryology
• Principal Investigator: Taiza Stumpp Teixeira
• Grantee: Helena Bertazolli Roloff
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

Primordial germ cells (PGC) derive from the epiblast and migrate through the primitive hindgut to reach the gonadal ridges. During this process, PGC undergo an epigenetic reprogramming that is marked by bulk DNA demethylation. This demethylation contributes to the reduction of potential epimutations and to paternal imprinting erasure. The ten-eleven translocation (TET) and thymine-DNA glycosilase (TDG) enzymes play an important role in the active genome demethylation. The TETs act on the conversion 5-methylcytosine (5mC) groups to 5hmC and TDG removes the intermediates of this first demethylation step. However, some regions of the genome escape this complete demethylation process, such as the transposable elements and specifically the retrotransposons. This escape represents a mechanism to matain the stability of the transgenerational characteristics transmitted through the germ cell, since the retrotransposons are potentially mutagenic. The aim of this project is to look at the presence of 5hmC mark in the retrotrasnposons IAP and LINE1 to get aditional information about the genome defence mechanisms related to epigenetics. We will also look at the quantitative expression of Tet1 and Tdg during rat PGC epigenetic reprogramming. (AU)