A urochordate putative homolog of human EB1, the protein which binds APC1

Abstract

The human EBI protein has been cloned by virtue of its interaction with the C-terminus of the APC (adenomatous polyposis coli) protein, whose C-terminal truncated forms have been shown to accompany sporadic and familial forms of colorectal cancer. We have cloned a putative EBI homolog from Botryllus schlosseri (Urochordata. Ascidiacea). The deduced protein is 287 amino acids long, and is identical with 48% of the residues in human EBI and 24-25% in two yeast hypothetical proteins. We propose that such a high degree of conservation among EBI homologs is indicative of an essential regulatory mechanism in eukaryotic cells.