Perfil de metilação do DNA e expressão gênica em regiões de DNA repetitivo associados a anormalidades na placentação em bezerros clonados

Abstract

This thesis is subdivided into three chapters and annexes: • Chapter 1: Theoretical rationale • Chapter 2: DNA methylation profile at a satellite region is associated with aberrant placentation in cloned calves • Chapter 3: DNA methylation and transcriptional profiles of endogenous retroviruses in placenta of cloned cattle • Attachments: Description of protocols; Article and published abstracts In Chapter 1 the intrinsic relationship between the nuclear transfer cloning technique and the epigenetic technique is demonstrated, providing the knowledge base necessary to understand the subjects that will be addressed in the other chapters. Chapter 2 is structured as a scientific paper and written in English. In this chapter we present methylation studies in regions of repetitive satellite DNA, which are present in multiple copies in the centromeric and pericentromeric regions of each chromosome of the organism. In addition, global methylation and hydroxymethylation analyzes of DNA were also performed. Evaluations were performed on placental samples from cloned calves and methylation levels were compared between animals considered healthy and those showing some aberrant phenotype. This article was recently published in the journal Placenta. Chapter 3 was also structured in a scientific paper format and written in English. In this chapter the participation of retrotransposons in the physiology of the host organism is suggested. DNA methylation studies and gene expression of genes originating from endogenous retroviruses involved in placentation, one of the critical processes in embryo clones, were carried out. This article will be submitted for publication in Plos One magazine. The protocols used in the experiments carried out in chapters 2 and 3 are described in annexes. The articles and published abstracts are attached.