Differential requirements of gag and gamma-actin domains for transforming potential of Gardner-Rasheed feline sarcoma virus.
The oncogene of Gardner-Rasheed feline sarcoma virus (GR-FeSV) encodes the 70-kilodalton protein containing gag(p15), gamma-actin, and fgr domains. To determine the role of these domains in the biological activity of P70gag-actin-fgr, we have constructed in-frame deletion and insertion mutants of GR-FeSV. We found, first, that the gamma-actin region could be deleted without affecting the transforming ability of these constructs, although an insertion mutant in the middle of the gamma-actin domain (map position 671) was partially defective in transformation and specifically had a reduced level of in vitro autophosphorylation activity. Second, mutations affecting the C-terminal third of the gag region appeared to abolish the ability to transform NIH 3T3 cells and autophosphorylation activity. These results suggest that the gamma-actin domain is not essentially required for the transforming activity of GR-FeSV but that it may take part in maintaining the conformational integrity of P70gag-actin-fgr and that the gag(p15) domain might have a critical role in modulating the function of P70gag-actin-fgr.
Miyoshi
J
J
Department of Oncogene Research, Osaka University, Japan.
Miyoshi
Y
Y
Sasai
H
H
Sakai
N
N
Katsumata
T
T
Kakunaga
T
T
D000199:Actins / Q000235:genetics*; D000818:Animals; D002460:Cell Line; D002472:Cell Transformation, Viral; D002872:Chromosome Deletion; D004252:DNA Mutational Analysis; D005786:Gene Expression Regulation; D015683:Gene Products, gag; D051379:Mice; D009856:Oncogene Proteins, Viral / Q000235:genetics*; D012190:Retroviridae / Q000235:genetics*; D012191:Retroviridae Proteins / Q000235:genetics*; D005253:Sarcoma Viruses, Feline / Q000235:genetics*; D013329:Structure-Activity Relationship; D014760:Viral Fusion Proteins / Q000235:genetics*
D000199:Actins; D015683:Gene Products, gag; D009856:Oncogene Proteins, Viral; D012191:Retroviridae Proteins; D014760:Viral Fusion Proteins