title: Bovine papillomavirus E1 protein is sumoylated by the host cell Ubc9 protein.
abstract: Papillomavirus E1 protein is the replication initiator that recognizes and binds to the viral origin and initiates DNA strand separation through its ATP-dependent helicase activity. The E1 protein also functions in viral DNA replication by recruiting several cellular proteins to the origin, including host DNA polymerase alpha and replication protein A. To identify other cellular proteins that interact with bovine papillomavirus E1, an HeLa cDNA library was screened using a yeast two-hybrid assay. The host cell sumoylating enzyme, Ubc9, was found to interact specifically with E1 both in vitro and in vivo. Mapping studies localized critical E1 sequences for interaction to amino acids 315-459 and strongly implicated leucine 420 as critical for E1.Ubc9 complex formation. In addition to binding E1, Ubc9 catalyzed the covalent linkage of the ubiquitin-like protein, SUMO-1, to E1. An E1 mutant unable to bind Ubc9 showed normal intracellular stability, but was impaired for intranuclear distribution. Failure to accumulate in appropriate nuclear subdomains may account for the previously demonstrated replication defect of a human papillomavirus 16 E1 protein that was also unable to bind Ubc9 and suggests that sumoylation is a functionally important modification with regulatory implications for papillomavirus replication.
authors.affiliation: Department of Medical Microbiology and Immunology, Texas A&M University System Health Science Center, College Station, Texas 77843-1114, USA.
authors.forename: D
authors.initials: D
authors.lastname: Rangasamy
authors.forename: V G
authors.initials: VG
authors.lastname: Wilson
mesh_terms: D000595:Amino Acid Sequence; D052688:Bovine papillomavirus 1; D002451:Cell Compartmentation; D002467:Cell Nucleus / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000378:metabolism*; D008025:Ligases / Q000378:metabolism*; D008969:Molecular Sequence Data; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D009856:Oncogene Proteins, Viral; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D025842:SUMO-1 Protein; D017386:Sequence Homology, Amino Acid; D020798:Two-Hybrid System Techniques; D044763:Ubiquitin-Conjugating Enzymes; D014452:Ubiquitins / Q000378:metabolism*; D014764:Viral Proteins / Q000378:metabolism*; D000098843:Ubiquitin-Conjugating Enzyme UBC9
chemical_list: D004268:DNA-Binding Proteins; C069814:E1 protein, Bovine papillomavirus; C093478:E1 protein, Human papillomavirus 16; D015513:Oncogene Proteins; D009856:Oncogene Proteins, Viral; D025842:SUMO-1 Protein; D014452:Ubiquitins; D014764:Viral Proteins; D044763:Ubiquitin-Conjugating Enzymes; D008025:Ligases; D000098843:Ubiquitin-Conjugating Enzyme UBC9