476A Poster - 06. Regulation of gene expression
Thursday April 07, 2:00 PM - 4:00 PM
Establishing the Role of the Conserved TN Domain in Tinman
Authors: Cayleen Bileckyj; Richard Cripps
Affiliation: San Diego State University
Keywords: c. activators/coactivators; j. cardiovascular disease
Congenital heart disease (CHD) is a major factor in mortality and morbidity in children and adults. Even though there has been substantial progress in detection and treatment, not all congenital heart defects can be identified early on through physical screenings. To advance our abilities to identify and manage CHD, we need to further understand the key genetic factors involved in causing these maladies.
Since Drosophila melanogaster shares similar cardiac developmental mechanisms with humans, it has been an essential model for human heart development. One similarity occurs between Tinman (Tin), a transcription factor in Drosophila necessary for the differentiation of cardiac cells, and its mammalian ortholog NK2 Homeobox 5 (Nkx2.5). These proteins share two conserved regions: the homeobox domain and the tin (TN) domain. Although the TN domain is completely conserved between these two proteins, there is little known about its significance.
By utilizing CRISPR/Cas9 gene editing, I established a line of Drosophila containing an in-frame deletion of the TN domain. Staining Drosophila embryos for NMR, a marker of cardial cells, revealed mutant embryos generate a significantly higher number of cardial cells when compared to wild type embryos (p<0.01). I also stained embryos for Tin and Svp, a protein important for heart development in Drosophila, to determine if the deletion of the TN domain affected cardial cell specification. Mutant embryos contained more cells expressing tin and more cells expressing svp than wild type embryos. These results support the importance of the TN domain in heart development and indicate the increase in cardial cells occurs before cardial cells differentiate into cells exclusively expressing tin or svp.
Tin and Nkx2.5 are vital to proper heart development. Characterizing the role of the conserved TN domain in these transcription factors provides the opportunity to vastly improve our understanding of the mechanisms involved in cardiac formation and maturation.