Meeting Abstract

53.5  Jan. 6  Identification of a potential ancient skin calmodulin gene from the sea lamprey ZHANG, Ziping*; LI, Weiming; Michigan State University zipingcn@msu.edu

The development and structure of integument systems differ significantly between vertebrates and invertebrates. In vertebrates, keratinocytes undergo a complex and Ca2+ dependent differentiation to form a real skin. This process is absent in invertebrates. Calmodulin (CaM) is a calcium binding protein that is involved in the regulation of multiple calcium-mediated functions. Generally, CaMs which contain four calcium-binding domains (EF-hand) are derived from an ancestral one-domain precursor by two gene duplications. Recently, two skin CaM related factor genes (scrfs) have been identified and proposed to play some roles in the epidermal differentiation. Skin related calmodulin genes have not been identified from non-mammalian vertebrates or invertebrates. Using a custom-made cDNA microarray, we identified a potential ancient skin CaM gene from a jawless vertebrate, the sea lamprey (Petromyzon marinus) termed as slcam4 which showed 66% similarity to mouse cam 4 (scarf) at amino acid sequence level. Slcam 4 encodes a protein of 73 amino acids which is only a half of the size of most CaM. And more interestingly, SLCaM 4 contains only two EF-hand domains. Furthermore, SLCaM 4 is an alkaline protein, as apposed to most of the other CaMs that are acidic. Like mouse CaM 4, SLCaM 4 does not have myristoylation sites. In situ hybridization showed epidermis-specific expression of slcam4 in sea lamprey embryo. To shed light on the origin of skin related CaM and its contribution to evolution of skin, further investigation to study the origination and characterization of this gene and its potential role in skin formation is being carried out. *This work is funded by the Great Lakes Fishery Commission.