title: Identification of essential trans-acting regions required for DNA replication of the Orgyia pseudotsugata multinucleocapsid nuclear polyhedrosis virus: lef-1 is an essential replication gene.
abstract: A transient replication assay for the identification of baculovirus genes that are essential for replication of an origin-containing reporter plasmid was established for the Orgyia pseudotsugata multinucleocapsid nuclear polyhedrosis virus (OpMNPV). Using a replication origin located on the OpMNPV HindIII-N fragment, we identified a subset of cosmids and plasmids from an OpMNPV cosmid library that was able to supply all the essential trans-acting factors and support replication of the origin-containing plasmid in uninfected Lymantria dispar cells. However, this limited set of DNA's was unable to support replication of a second origin-containing plasmid derived from a different region of the OpMNPV genome. Replication analysis of deletion clones of the HindIII-N fragment led to the identification of a gene, late expression factor 1 (lef-1), that is essential for the transactivation of DNA replication in this system. Transcriptional analysis of lef-1 mapped both early and late transcripts of about 1.75 kb. A motif characteristic of nucleoside triphosphate-binding sites present in the carboxy-terminal region of AcMNPV Lef-1 is not conserved in OpMNPV Lef-1.
authors.affiliation: Genetics Program, Oregon State University, Corvallis 97331-7301.
authors.forename: C H
authors.initials: CH
authors.lastname: Ahrens
authors.forename: G F
authors.initials: GF
authors.lastname: Rohrmann
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004261:DNA Replication / Q000235:genetics*; D004279:DNA, Viral / Q000096:biosynthesis / Q000235:genetics; D005814:Genes, Viral; D016679:Genome, Viral; D007313:Insecta / Q000821:virology; D008969:Molecular Sequence Data; D017924:Nucleopolyhedroviruses / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D015533:Transcriptional Activation; D014162:Transfection; D014764:Viral Proteins / Q000235:genetics
chemical_list: D004279:DNA, Viral; D014764:Viral Proteins; C081258:late expression factor 1, baculovirus