Alternative splicing and tissue specific expression of the 5′ truncated bCCE 1 variant bCCE 1Δ514

Abstract

In many non-excitable as well as electrically excitable cells, depletion of intracellular Ca²⁺ stores after stimulation of G protein coupled receptors or receptor tyrosine kinases is followed by Ca²⁺ entry across the plasma membrane, a mechanism referred to as capacitative calcium entry (CCE) [Putney, J.W., Cell Calcium 11 (1990) 611–624; Fasolato, C. et al., Trends Pharmacol Sci. 15 (1994) 77–83]. Recently, we reported that bCCE 1, a homologue of the Drosophila protein trp, exhibits the characteristics of CCE channels [Philipp, S. et al., EMBO J. 15 (1996) 6166–6171]. In this study, we report the cloning of a 5′ truncated splice variant (bCCE 1Δ₅₁₄) of the full-length bCCE 1. The bCCE 1Δ₅₁₄ cDNA encodes a protein of 486 amino acids with the ATG triplet encoding M⁵¹⁴ of bCCE 1 as translation initiation codon and, therefore, comprises two putative transmembrane segments corresponding to the predicted transmembrane segments 5 and 6 of bCCE 1. bCCE 1Δ₅₁₄ transcripts appear to be specifically expressed in the adrenal gland and genome analysis reveals an alternative splice site within an exon of the CCE 1 gene leading to the formation of bCCE 1Δ₅₁₄.