Separation of host range from transformation functions of the hr-t gene of polyomavirus. Journal Article uri icon



  • hr-t mutants of polyomavirus are defective in virus growth as well as in cell transformation, and have genetic alterations that invariably affect both the middle and small T proteins. We have examined the growth properties of three site-directed mutants that either eliminate or alter the middle T without affecting the small T protein. Mutant 808A encodes large and small T proteins but no middle T; it grew poorly in NIH 3T3 cells. In contrast, mutants 1387T and 1178T which express altered middle T along with normal large and small T proteins grew nearly as well as wild-type virus. Thus, although the altered middle T proteins encoded by 1387T and 1178T are defective for cell transformation, they retained the ability to induce expression of a cellular permissivity factor(s) required for virus production. At the biochemical level, the induction of permissivity by middle T was manifested primarily in terms of phosphorylation ofVP1 on threonine and in efficient encapsidation of viral DNA to form infectious virus. The natural role of middle T involves regulation of phosphorylation events, and can be enacted, at least in part, independently of interactions withpp60c-src.

publication date

  • January 1, 1989

Date in CU Experts

  • October 1, 2013 11:25 AM

Full Author List

  • Garcea RL; Talmage DA; Harmatz A; Freund R; Benjamin TL

author count

  • 5

Additional Document Info

start page

  • 312-9

end page

  • 312-9


  • 168


  • 2