Complete nucleotide sequence of an infectious clone of Friend spleen focus-forming provirus: gp55 is an envelope fusion glycoprotein.

AUTOR(ES)

Clark, S P

RESUMO

The Friend spleen focus-forming provirus is 6,296 base pairs (bp) in length. Compared to Moloney murine leukemia virus, it has undergone five major deletions, three substitutions, and a number of minor alterations. Otherwise, these viruses are about 90% homologous. A 16-bp palindrome is found in the region thought to be involved in packaging and dimerization of the RNA genome. Premature termination of translation of the gag polyprotein is attributed to a 13-bp deletion in the p12 region. A substitution of xenotropic env sequences was identified in the 5' region of the env gene; 150 nucleotides 3' to this substitution, a deletion of 585 bp removes the site where the normal env precursor protein is cleaved to form gp70 and p15(E), resulting in a fusion protein of Mr 44,725. Due to these changes, the env product gp55 is expected to have a substantially different conformation on the cell surface compared to either a xenotropic or ecotropic gp70 protein, and may be responsible for the rapid erythroleukemic potential of spleen focus-forming virus.

Documentos Relacionados

• The erythropoietin receptor transmembrane region is necessary for activation by the Friend spleen focus-forming virus gp55 glycoprotein.
• Complete nucleotide sequence of the gene for the specific glycoprotein (gp55) of Friend spleen focus-forming virus.
• Fusion of the erythropoietin receptor and the Friend spleen focus-forming virus gp55 glycoprotein transforms a factor-dependent hematopoietic cell line.
• Friend spleen focus-forming virus glycoprotein gp55 interacts with the erythropoietin receptor in the endoplasmic reticulum and affects receptor metabolism.
• Env-derived gp55 gene of Friend spleen focus-forming virus specifically induces neoplastic proliferation of erythroid progenitor cells.