Expression and Functional Characterization of <i>Xhmg-at-hook</i> Genes in <i>Xenopus laevis</i>

<div><p>High Mobility Group A proteins (HMGA1 and HMGA2) are architectural nuclear factors involved in development, cell differentiation, and cancer formation and progression. Here we report the cloning, developmental expression and functional analysis of a new multi-AT-hook factor in <i>Xenopus laevis</i> (XHMG-AT-hook) that exists in three different isoforms. <i>Xhmg-at-hook1</i> and <i>3</i> isoforms, but not isoform <i>2</i>, are expressed throughout the entire development of <i>Xenopus</i>, both in the maternal and zygotic phase. Localized transcripts are present in the animal pole in the early maternal phase; during the zygotic phase, mRNA can be detected in the developing central nervous system (CNS), including the eye, and in the neural crest. We show evidence that XHMG-AT-hook proteins differ from typical HMGA proteins in terms of their properties in DNA binding and in protein/protein interaction. Finally, we provide evidence that they are involved in early CNS development and in neural crest differentiation.</p></div>