title: A novel 50-kilodalton fragment of host cell factor 1 (C1) in G(0) cells.
abstract: Host cell factor 1 (HCF-1; also called C1) is a 230-kDa protein which is cleaved posttranslationally into separate but associated N- and C-terminal polypeptides. These polypeptides are components of the C1 complex, along with Oct-1 and the viral protein VP16. The C1 complex is formed when herpes simplex virus (HSV) infects a cell and is responsible for transcription of the HSV immediate-early genes. A temperature-sensitive mutation in the N-terminal kelch domain of HCF-1 reversibly arrests cells in a G(0)-like state when grown at the nonpermissive temperature, and the same domain interacts with VP16 in the formation of the C1 complex. The form of HCF-1 in primary G(0) cells was investigated by using peripheral blood mononucleocytes and serum-arrested human primary fibroblasts. A novel 50-kDa N-terminal fragment of HCF-1 encompassing the kelch domain was identified in the cytoplasm of these cells. This fragment arises by proteolysis of the full-length HCF-1 protein and is able to associate with VP16.
authors.affiliation: Center for Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: R B
authors.initials: RB
authors.lastname: Scarr
authors.forename: M R
authors.initials: MR
authors.lastname: Smith
authors.forename: M
authors.initials: M
authors.lastname: Beddall
authors.forename: P A
authors.initials: PA
authors.lastname: Sharp
mesh_terms: D002352:Carrier Proteins; D004268:DNA-Binding Proteins / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology; D017405:Herpes Simplex Virus Protein Vmw65 / Q000378:metabolism*; D051863:Host Cell Factor C1; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology; D050811:Octamer Transcription Factor-1; D010446:Peptide Fragments / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism*; D016192:Resting Phase, Cell Cycle / Q000502:physiology*; D018139:Simplexvirus; D014157:Transcription Factors / Q000378:metabolism; D017735:Virus Latency
chemical_list: D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C497692:HCFC1 protein, human; D017405:Herpes Simplex Virus Protein Vmw65; D051863:Host Cell Factor C1; D050811:Octamer Transcription Factor-1; C494165:POU2F1 protein, human; D010446:Peptide Fragments; D011506:Proteins; D014157:Transcription Factors