CRIPTO3, a presumed pseudogene, is expressed in cancer

• Published in: Biochemical and biophysical research communications 2008-12, Vol.377 (1), p.215-220
• Main Authors: Sun, Chao, Orozco, Olivia, Olson, Dian L., Choi, Eugene, Garber, Ellen, Tizard, Rich, Szak, Suzanne, Sanicola, Michele, Carulli, John P.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Cancer; Cell Line, Tumor; Cell Transformation, Neoplastic - genetics; CRIPTO; Epidermal Growth Factor - genetics; Gene expression; Gene Expression Regulation, Neoplastic; Genes, Neoplasm; GPI-Linked Proteins; Humans; Intercellular Signaling Peptides and Proteins; Membrane Glycoproteins - genetics; Molecular Sequence Data; Neoplasm Proteins - genetics; Neoplasms - genetics; Pseudogenes; Retrogene; RT-PCR; TDGF; Transcription, Genetic
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2008.09.113

Cripto is a cell surface protein highly expressed in certain solid tumors, and overexpression of Cripto protein is oncogenic. Cripto-1 protein is encoded by CRIPTO1 gene. CRIPTO3, a presumed pseudogene, has an open reading frame with six amino acid differences from Cripto-1. We show that CRIPTO3 mRNA is the CRIPTO message expressed in many cancer samples. A CRIPTO3 SAGE tag was found in several cancer SAGE libraries, while the CRIPTO1 tag was found in ES cell libraries. In vitro experiments indicate both Cripto-1 and Cripto-3 proteins are functional in the Nodal-dependent signal pathway. Our data indicate that CRIPTO3 is an expressed gene, particularly in certain cancers, and suggest a potentially novel mechanism of oncogenesis through activation of a retrogene.