|Enhanced malignant transformation induced by expression of a distinct protein domain of ribonucleotide reductase large subunit from herpes simplex virus type 2.
|Year of Publication
|Ali MA, McWeeney D, Milosavljević A, Jurka J, Jariwalla RJ
|Proc Natl Acad Sci U S A
|1991 Sep 15
|Amino Acid Sequence, Animals, Cell Transformation, Viral, Cells, Cultured, Chlorocebus aethiops, Cloning, Molecular, DNA Mutational Analysis, DNA, Viral, Genes, Viral, Macromolecular Substances, Molecular Sequence Data, Oncogenes, Protein Kinases, Rats, Ribonucleotide Reductases, Sequence Alignment, Simplexvirus, Viral Structural Proteins
The 1.3-kilobase (kb) Pst I DNA fragment C (Pst I-C) of herpes simplex virus type 2 (HSV-2) morphological transforming region III (mtrIII; map unit 0.562-0.570) encodes part of the N-terminal half of the large subunit of ribonucleotide reductase (RR1; amino acid residues 71-502) and induces the neoplastic transformation of immortalized cell lines. To assess directly the role of these RR1 protein sequences in cell transformation, the Pst I-C fragment was cloned in an expression vector (p91023) containing an adenovirus-simian virus 40 promoter-enhancer to generate recombinant plasmid p9-C. Expression of a protein domain (approximately 65 kDa) was observed in p9-C-transfected COS-7 and Rat2 cells but not in those transfected with plasmid pHC-14 (Pst I-C in a promoterless vector). In Rat2 cells, p9-C induced highly transformed foci at an elevated frequency compared with that of pHC-14. Introduction of translation termination (TAG) condons within the RR1 coding sequence and within all three reading frames inactivated RR1 protein expression from p9-C and reduced its transforming activity to the level seen with the standard pHC-14 construct. Wild-type p9-C specified a protein kinase capable of autophosphorylation. Computer-assisted analysis further revealed significant similarity between regions of mtrIII-specific RR1 and amino acid patterns conserved within the proinsulin precursor family and DNA transposition proteins. These results identify a distinct domain of the HSV-2 RR1 protein involved in the induction of enhanced malignant transformation. In addition, the data indicate that the mtrIII DNA itself can induce basal-level transformation in the absence of protein expression.
|Proc. Natl. Acad. Sci. U.S.A.
|PubMed Central ID
|CA 42467 / CA / NCI NIH HHS / United States