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Sequencing and computer analysis of the left (52,283 bp) and right (49,649 bp) variable DNA regions of the cowpox virus strain GRI-90 (CPV-GRI) has revealed 51 and 37 potential open reading frames (ORFs), respectively. Comparison of the structure–function organization of these DNA regions of CPV-GRI with those previously published for corresponding regions of genomes of vaccinia virus, strains Copenhagen (VAC-COP) and Western Reserve (VAC-WR); and variola major virus, strains India-1967 (VAR-IND), Bangladesh-1975 (VAR-BSH); and alastrim variola minor virus, strain Garcia-1966 (VAR-GAR), was performed. Within the left terminal region under study, an extended DNA sequence (14,171 bp), unique to CPV, has been found. Within the right region of the CPV-GRI genome two segments, which are unique to CPV DNA (1579 and 3585 bp) have been found. Numerous differences have been revealed in the genetic structure of CPV-GRI DNA regions, homologous to fragments of the genomes of the above-mentioned orthopoxvirus strains. A cluster of ORFs with structural similarity to immunomodulatory and host range function of other poxviruses have also been detected. A comparison of the sequences of ORF B, crmA, crmB, crmC, IMP, and CHO hr genes of CPV Brighton strain (CPV-BRI) with the corresponding genes in strain GRI-90 have revealed an identity at the amino acid level ranging from 82 to 96% between the two strains. The findings are significant in light of the recent demonstration of CPV as an important poxvirus model system to probe the precise in vivo role(s) of the unique virally encoded immunomodulatory proteins. Also, the presence of a complete and intact repertoire of immunomodulatory proteins, ring canal proteins family, and host range genes indicates that CPV may have been the most ancient of all studied orthopoxviruses.

Monkeypox virus (MPV) belongs to the orthopoxvirus genus of the family Poxviridae, is endemic in parts of Africa, and causes a human disease that resembles smallpox. The 196,858-bp MPV genome was analyzed with regard to structural features and open reading frames. Each end of the genome contains an identical but oppositely oriented 6379-bp terminal inverted repetition, which similar to that of other orthopoxviruses, includes a putative telomere resolution sequence and short tandem repeats. Computer-assisted analysis was used to identify 190 open reading frames containing ≥60 amino acid residues. Of these, four were present within the inverted terminal repetition. MPV contained the known essential orthopoxvirus genes but only a subset of the putative immunomodulatory and host range genes. Sequence comparisons confirmed the assignment of MPV as a distinct species of orthopoxvirus that is not a direct ancestor or a direct descendent of variola virus, the causative agent of smallpox.

Monkeypox virus (MPV) causes a human disease which resembles smallpox but with a lower person-to-person transmission rate. To determine the genetic relationship between the orthopoxviruses causing these two diseases, we sequenced the 197-kb genome of MPV isolated from a patient during a large human monkeypox outbreak in Zaire in 1996. The nucleotide sequence within the central region of the MPV genome, which encodes essential enzymes and structural proteins, was 96.3% identical with that of variola (smallpox) virus (VAR). In contrast, there were considerable differences between MPV and VAR in the regions encoding virulence and host-range factors near the ends of the genome. Our data indicate that MPV is not the direct ancestor of VAR and is unlikely to naturally acquire all properties of VAR.

The initiation sites of the Galleria mellonella L. nuclear polyhedrosis virus (G.m. NPV) DNA replication were revealed. For this purpose SCLd 135 cells permitting the G.m. NPV productive reproduction were transformed by the recombinant plasmids containing the viral genome individual fragments in pRSF 2124 and pBR 322 vectors. It was revealed that 2 of the 32 recombinant plasmids can autonomously replicate in the eucaryotic cells. According to the Maxam-Gilbert method the DNA G.m. NPV fragment (1300 bp) primary structure of pHBR plasmid was determined. The structure analysis revealed the typical regulator signals as in the replicons. The possible regulation mechanisms of the DNA G.m. NPV synthesis initiation was supposed.

It is well known now that the main regulation stages of bacteriophage X development occur on the level of transcription. The regulation of transcription does not occur only at the initiation stage but also at the termination stage. It has been shown that at the early steps of phage )t development the regulation of termination is controlled by phage-specific protein, product ofgeneN. This protein provides anti-termination of RNA originating from promoters PL and PR [1-51. At the late stage of the phage ~, development, promoter PR' is used for the effective transcription of the lysis and morphology genes [5-8]. A product of X gene Q is necessary for efficient synthesis of/ate messenger RNA origination from PR' (reviews [5,8]). Protein Q seems not to be an activator of the promoter PR', but to provide elongation of the short 6 S RNA promoted by PR' [6,7,9]. It has been proposed [5,6] that this transcript is a 'leader sequence' for late gene expression, and that protein Q, like protein N, is an anti-terminator protein. Here, we have determined the primary structure of the X DNA fragment between 90.8% and 93.1% of the ~ genome length. This fragment contains gene Q, promoter PR' and gene 6 S RNA with its terminator. MspI, HindIII and TagI were isolated according to [13]. DNA-ligase and polynucleotide kinase were kindly provided by Dr Yu. S. Nechaev and alk',dine phosphatase and DNA polymerase I (Klenov's fragment) by Dr V. G. Korobko. Xci857 DNA was isolated as in [9]. A plasmid DNA was isolated according to [14]. [')'-32p]ATP, [o~-3zpldAYP and [c~-32pIdGTP with spec. act. 2000-3000 Ci/mmol were purchased from Amersham Radiochemical Centre (England). DNA hydrolysis by restriction endonucleases was performed under the conditions in [ 15]. Electrophoresis of the DNA fragments in 1% agarose or 4% polyacrylamide gels and isolation of the fragments from the gels were performed as in [9].