Expression analysis of integrin β1 isoforms during zebrafish embryonic development.

Integrins are a superfamily of the major metazoan receptors for cell-cell and cell-extracellular matrix adhesion. Integrins and their ligands play critical roles in a variety of fundamental cellular processes. Integrins are heterodimeric cell surface glycoproteins comprised of non-covalently bound α- and β-subunits. A variety of integrin subunits have been identified in mouse, chicken, zebrafish, Xenopus laevis and other vertebrates. In zebrafish multiple integrin β1 homologs have been identified. However, zebrafish embryo is a largely untapped model for analyzing integrin β1 isoforms temporal-spatial expression pattern, function and its relevance to human disease in whole animal level. Currently, we systematically analyzed the expression pattern of zebrafish integrin β1 including integrin beta 1a (itgb1a), integrin beta 1b (itgb1b), integrin beta 1b.1 (itgb1b.1), and integrin beta 1b.2 (itgb1b.2) at embryo stage using whole amount in situ hybridization. We show itgb1a, itgb1b and itgb1b.1 were maternally expressed in zygote, cleavage and blastula periods, while itgb1b.2 was not detectable in the corresponding stages. A more tissue specific pattern emerges during organogenesis, including heart expression for itgb1a, myotome borders for itgb1b, intestinal epithelium for itgb1b.1, and branchial arch for itgb1b.2. All are similarly expressed in the early embryonic epidermis and notochord. Additionally, itgb1a, itgb1b and itgb1b.2 shared the common expression in otic vesicle. Our study provides new insight into the integrin β1 expression and the use of this model organism to tackle future studies on the role of integrin β1 in embryo development.