8 - Regulation of Gap Junction Protein Genes in Differentiating ES cells

Abstract

This chapter briefly introduces the gap junction structure, connexin genes, and gap junctional communication in embryogenesis and development. Gap junctions are cell–cell-communicating junctions that consist of multimeric proteins called connexins. They mediate the exchange of low molecular-weight metabolites and ions between contacting cells. It has been hypothesized that they play a crucial role in the maintenance of homeostasis, morphogenesis, cell differentiation, and growth control in multicellular organisms. The recent discovery that human genetic disorders are associated with mutations in connexin genes and experimental data on connexin knockout mice have provided direct evidence that gap junctional communication is essential for tissue functions and organ development. Investigations of gap junctional communication and connexin expression have shown that the expression of multiple connexins is differentially regulated during the differentiation of embryonic stem (ES) cells in vitro, such as cardiomyocyte differentiation and neuronal differentiation.