Herpes simplex virus types 1 and 2 homology in the region between 0.58 and 0.68 map units

Abstract

The homology between herpes simplex virus type 1 and type 2 (HSV-1 and HSV-2, respectively) DNA between 0.58 and 0.674 map units was compared by Southern and dot blot analysis with DNA of one type of virus as a hybridization probe against the other type. Regions of high homology were interspersed with regions of detectably lower homology. However, only one region (between 0.647 and 0.653 map units) contained few or no homologous sequences. In situ RNA blot hybridization demonstrated that the mRNA species transcribed in the right-hand portion of the region are homologous between HSV-1 and HSV-2, as was previously found for the left-hand portion. A 2.7-kilobase HSV-2 transcript in the right-hand portion of the studied region was clearly that encoding HSV-2 glycoprotein C. Comparative nucleotide sequence analysis of specific regions demonstrated that homologous translational reading frames could be identified in the virus types. This analysis also demonstrated that homology could be abruptly lost outside such reading frames. Comparison of regions of homology with published HSV-1 transcription maps suggests that there can also be large divergence within translational reading frames. Some, but not complete, sequence homology was seen in the putative promoter sequence for the 730-base HSV-1 mRNA mapping to the right of glycoprotein C and the corresponding HSV-2 DNA. This suggests that the rather strict conservation of promoter sequences between homologous HSV-1 and HSV-2 transcripts seen in other regions of the genome may not be a necessary feature between these virus types.

Characterization of the gene encoding herpes simplex virus type 2 glycoprotein C and comparison with the type 1 counterpart

“…The start of transcription of the 730-bp message is at nucleotide 2390. Upstream from the cap site is the sequence TTATAA (2361 through 2366), suggesting that this mRNA is under the control of its own promoter and consistent with the observation that the 730-base mRNA could not be detected by Northern blot analysis with fragments of DNA upstream of this site as probes (8). The first ATG after the start of transcription was located 102 nucleotides downstream at nucleotides 2491 through 2493.…”

“…The predicted weight of the gC protein is 51,600 as compared with the observed value of 60,000. No apparent polyadenylation signal could be found following the termination codon for gC-2 consistent with the apparent size of the mRNA as estimated on Northern blots (8) and with the mapping of the HSV-1 message which places the 3' terminus ca. 1 kb further downstream.…”

“…The most abundant species was ca. 2.5 kb, the same size or slightly smaller than the message encoding gC-1 (8,12). Also detectable was a 730-base message corresponding in size to the HSV-1 message encoding a 17.8K protein.…”

“…Characterization of the RNA and protein products. By hybridization analysis, the region of the HSV-1 genome delineated by map coordinates 0.58 to 0.674 showed regions of high homology interspersed with regions of considerably lower homology and one region with no detectable homology (8). We have determined the nucleotide sequence of a 3.4-kb segment of HSV-2 DNA from map coordinates 0.61 to 0.644 which encodes glycoprotein C and an 18K protein.…”

“…Preliminary information about the HSV-2 gC gene was obtained by studying the intertypic homology between 0.58 and 0.68 m.u. (8). At the 5' end of gC and within the 3' sequences encoding the 18K protein, there is moderate intertypic homology.…”