Molecular characterization and leukocyte distribution of a teleost β1 integrin molecule

The β1 integrin, in combination with the alpha subunit, is responsible for migration of leukocytes into areas of inflammation. Although identified in mammalian species; the β1 or CD29 molecule has yet to be identified in fish. The present investigation has identified a full-length channel catfish, Ictalurus punctatus, cDNA β1 molecule composed of 2786 bases and a deduced amino acid sequence of 797 amino acids. The catfish molecule has an amino acid identity ranging from 71.87 to 74.12% with bovine, feline, human, and Xenopus. The channel catfish molecule retains several characteristics of mammalian β1 molecules, such as four cysteine-rich repeat regions, and eight potential N-linked glycosylation sites. Based on Western blotting the channel catfish β1 molecule has a molecular mass of approximately 130 kDa, essentially the same as that for mammalian species. These results confirm the existence and expression of a β1 gene in channel catfish, a species phylogenetically distant from mammals.