Chick heart/hemangioblast progenitor 12 (chep 12: study of a novel gene expressed in the heart/hemangioblast percursors cells

Dissertação de mest., Ciências Biomédicas, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2009

Establishment of the biochemical and molecular nature of cardiac development is essential to understand the relationship between genetic and morphological aspects of heart formation. The need to identify genes that are differentially expressed between cell populations within the embryo and within the embryonic heart is critical to elucidate the complex processes of heart development. With this in mind, our laboratory focused on the identification and study of novel genes expressed and involved in the correct development of the vertebrate heart/hemangioblast precursor cell (HPC) lineages. A differential screening using Affymetrix GeneChip Chick system was performed, leading to the identification of several new genes expressed in the haematopoiesis, angiogenesis or cardiogenesis precursor lineages. One of these novel genes, initially denominated CHEP12 (Chick Heart/Hemangioblast Progenitor 12), encodes for a novel secreted protein that contains a Calcium-binding EGF-like domain. Additionally, it was found that besides the canonical CHEP12 transcript, there are several alternative-spliced form variants, indicating that several isoform proteins may be synthesized in response to different signals. The current study intends to accomplish a detailed characterization of the expression pattern of the canonical CHEP12 gene and one of its alternative-spliced form variant (CHEP12-A). WISH and histological sections allowed us to suggest that CHEP12 may be involved in cardiogenic processes due to its expression in the Secondary Heart Field. Moreover, CHEP12 might also be implicated in the development of the venous system as its expression was also detected in the anterior, posterior and common cardinal veins. In addition, comparison between the expression pattern of the full transcript CHEP12 and its isoform CHEP12-A showed no significant differences.