Phylogenetic analysis and possible function of bro-like genes, a multigene family widespread among large double-stranded DNA viruses of invertebrates and bacteria.
Baculovirus repeated open reading frame (bro) genes and their relatives constitute a multigene family, typically with multiple copies per genome, known to occur among certain insect dsDNA viruses and bacteriophages. Little is known about the evolutionary history and function of the proteins encoded by these genes. Here we have shown that bro and bro-like (bro-l) genes occur among viruses of two additional invertebrate viral families, Ascoviridae and Iridoviridae, and in prokaryotic class II transposons. Analysis of over 100 sequences showed that the N-terminal region, consisting of two subdomains, is the most conserved region and contains a DNA-binding motif that has been characterized previously. Phylogenetic analysis indicated that these proteins are distributed among eight groups, Groups 1-7 consisting of invertebrate virus proteins and Group 8 of proteins in bacteriophages and bacterial transposons. No bro genes were identified in databases of invertebrate or vertebrate genomes, vertebrate viruses and transposons, nor in prokaryotic genomes, except in prophages or transposons of the latter. The phylogenetic relationship between bro genes suggests that they have resulted from recombination of viral genomes that allowed the duplication and loss of genes, but also the acquisition of genes by horizontal transfer over evolutionary time. In addition, the maintenance and diversity of bro-l genes in different types of invertebrate dsDNA viruses, but not in vertebrate viruses, suggests that these proteins play an important role in invertebrate virus biology. Experiments with the unique orf2 bro gene of Autographa californica multicapsid nucleopolyhedrovirus showed that it is not required for replication, but may enhance replication during the occlusion phase of reproduction.
Bideshi
Dennis K
DK
California Baptist University, 8432 Magnolia Avenue, Riverside, CA 92504-3297, USA.|Department of Entomology and Interdepartmental Graduate Program in Genetics, University of California, Riverside, CA 92521, USA.
Renault
Sylvaine
S
Laboratoire d'Etude des Parasites Génétiques, FRE CNRS 2535, Université François Rabelais, UFR des Sciences et Techniques, Parc de Grandmont, 37200 Tours, France.
Stasiak
Karine
K
Laboratoire d'Etude des Parasites Génétiques, FRE CNRS 2535, Université François Rabelais, UFR des Sciences et Techniques, Parc de Grandmont, 37200 Tours, France.|Department of Entomology and Interdepartmental Graduate Program in Genetics, University of California, Riverside, CA 92521, USA.
Federici
Brian A
BA
Department of Entomology and Interdepartmental Graduate Program in Genetics, University of California, Riverside, CA 92521, USA.
Bigot
Yves
Y
Laboratoire d'Etude des Parasites Génétiques, FRE CNRS 2535, Université François Rabelais, UFR des Sciences et Techniques, Parc de Grandmont, 37200 Tours, France.|Department of Entomology and Interdepartmental Graduate Program in Genetics, University of California, Riverside, CA 92521, USA.
D000595:Amino Acid Sequence; D029223:Ascoviridae / Q000235:genetics* / Q000472:pathogenicity; D001419:Bacteria / Q000821:virology*; D003001:Cloning, Molecular; D016384:Consensus Sequence; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D022761:Gene Transfer, Horizontal; D005814:Genes, Viral; D007497:Iridoviridae / Q000235:genetics* / Q000472:pathogenicity; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics / Q000502:physiology*; D010802:Phylogeny; D011995:Recombination, Genetic; D016415:Sequence Alignment; D014157:Transcription Factors / Q000235:genetics*; D014779:Virus Replication
C105840:Bro protein, Drosophila; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D014157:Transcription Factors