"Replacement" of COOH-terminal truncation of v-fms with c-fms sequences markedly reduces transformation potential.

AUTOR(ES)

Browning, P J

RESUMO

Protooncogenes when transduced by retroviruses may undergo structural modifications that render their gene products oncogenic. The c-fms gene encodes a transmembrane protein with tyrosine kinase activity that is very similar or identical to the receptor for the monocyte-macrophage colony-stimulating factor. Its transforming homologue (v-fms) in the Susan McDonough strain feline sarcoma virus causes fibrosarcomas in cats. Molecular cloning and sequence analysis of the cDNA that encodes the cytoplasmic domain of the human c-fms gene shows that the product of the transduced viral homologue, v-fms, is truncated at the COOH-terminal end. The COOH-terminal 40 amino acids of the c-fms gene product are replaced in the v-fms gene product by 11 amino acids encoded by the retroviral genome. Hybrid v-fms/c-fms genes, in which either the entire cytoplasmic domain or the COOH-terminal coding sequences of the v-fms gene were replaced by the corresponding segments of the c-fms gene, had a reduced ability to transform fibroblasts despite a high level of encoded protein on the cell surface. These data indicate that the COOH-terminal modifications contribute to the transforming potential of the v-fms viral oncogene product.

Documentos Relacionados

• Reassessment of the v-fms sequence: threonine phosphorylation of the COOH-terminal domain.
• Tyrosine phosphorylations in vivo associated with v-fms transformation.
• A new acute transforming feline retrovirus with fms homology specifies a C-terminally truncated version of the c-fms protein that is different from SM-feline sarcoma virus v-fms protein.
• Transformation by the v-fms oncogene product: role of glycosylational processing and cell surface expression.
• Chromosomal localization of the human c-fms oncogene.