Reduction of Cripto-1 expression by a hammerhead-shaped RNA molecule results from inhibition of translation rather than mRNA cleavage.
Cripto-1 (CR-1) is a transforming growth factor which has been associated with breast, colon, and pancreatic cancer. Overexpression of CR-1 in non-tumorigenic mouse mammary epithelial cells and fibroblasts results in an increase in anchorage-dependent and -independent growth in vitro. Reduction of CR-1 expression in human colon carcinoma or embryonal teratoma cells results in a decrease in growth in vitro. In an effort to better define the role of CR-1 in breast cancer, we have developed an underexpression vector for CR-1 to reduce CR-1 levels in a tumorigenic mouse mammary epithelial cell line (-SA). This vector specifically targets the expression of the murine homolog of CR-1 in murine cancer lines and utilizes a hammerhead ribozyme-like structure directed toward the extreme 5' end of the Cripto-1 mRNA. We dramatically reduced expression of CR-1 through the expression of this RNA. This is the first use of a ribozyme-like molecule to alter Cripto-1 expression. This ribozyme-shaped molecule appears to act principally through a block in translation. A possible mechanism for this block is described, and its implications for modifying expression of other bioactive proteins are discussed.
Kintner
R L
RL
Department of Genetics & Cell Biology, Washington State University, Pullman 99164-4234, USA.
Hosick
H L
HL
D000818:Animals; D001483:Base Sequence; D014408:Biomarkers, Tumor / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D004815:Epidermal Growth Factor; D058851:GPI-Linked Proteins; D006133:Growth Substances / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D051379:Mice; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D009690:Nucleic Acid Conformation; D014176:Protein Biosynthesis; D016337:RNA, Catalytic / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D014408:Biomarkers, Tumor; D058851:GPI-Linked Proteins; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; D016337:RNA, Catalytic; D012333:RNA, Messenger; C070636:TDGF1 protein, human; C489450:Tdgf1 protein, mouse; D004815:Epidermal Growth Factor