IDENTIFICATION OF GENES ENCODING ZINC-FINGER PROTEINS, NONHISTONE CHROMOSOMAL HMG PROTEIN HOMOLOG, AND A PUTATIVE GTP PHOSPHOHYDROLASE IN THE GENOME OF CHILO IRIDESCENT VIRUS

Five RNA transcripts of about 1.2 to 1.7 kilobases were mapped to a pa rt of the genome of insect iridescent virus type 6 (Chile iridescent v irus; CIV) between genome coordinates 0.832 and 0.856 within the EcoRI DNA fragment F. The nucleotide sequence of this particular region (57 02 base pairs) of the CIV genome was determined. The DNA sequence cont ains a number of perfect direct, inverted, and palindromic repeats inc luding three clusters of tandemly organized repetitive DNA elements lo cated between the nucleotide positions 1534 to 1566, 3720 to 3780, and 4350 to 4450. Eight long open reading frames (ORFs; EF1 to 8) were de tected in the sequenced region of the CIV genome. ORF EF1 encodes a pu tative protein of 221 amino acid residues (aa) that is closely related to eukaryotic nonhistone chromosomal proteins of the high mobility gr oup (HMG) superfamily. Virus encoded homologues of HMG proteins have n ot been reported so far. The EF2 gene product (145 aa) contains a spec ific zinc finger motif and belongs to a distinct group of identified a nd putative zinc finger proteins including a second putative protein ( 239 aa) of CIV encoded in the EcoRI DNA fragment Y (1984 bp; 0.381 to 0.391 viral map units). The product of EF6 (127 aa) is related to D250 ORF product of African swine fever virus (ASFV) and belongs to the re cently described protein family sharing a highly conserved sequence mo tif with bacterial antimutator GTP phosphohydrolase MutT. Thus the seq uenced region of the CIV genome encodes three putative proteins which may be directly involved in the replication and/or transcription of th e viral DNA.