Glycoprotein gene sequence variation in rhesus monkey rhadinovirus

Abstract

Gene sequences for seven glycoproteins from 20 independent isolates of rhesus monkey rhadinovirus (RRV) and of the corresponding seven glycoprotein genes from nine strains of the Kaposi's sarcoma-associated herpesvirus (KSHV) were obtained and analyzed. Phylogenetic analysis revealed two discrete groupings of RRV gH sequences, two discrete groupings of RRV gL sequences and two discrete groupings of RRV gB sequences. We called these phylogenetic groupings gH(a), gH(b), gL(a), gL(b), gB(a) and gB(b). gH(a) was always paired with gL(a) and gH(b) was always paired with gL(b) for any individual RRV isolate. Since gH and gL are known to be interacting partners, these results suggest the need of matching sequence types for function of these cooperating proteins. gB phylogenetic grouping was not associated with gH/gL phylogenetic grouping. Our results demonstrate two distinct, distantly-related phylogenetic groupings of gH and gL of RRV despite a remarkable degree of sequence conservation within each individual phylogenetic group.

Figure 1

Phylogenetic trees of RRV glycoproteins with greatest variation. A) gH; B) gL; C) gB. The trees were obtained with the Neighbor-Joining algorithm using the Kimura 2 parameter distance correction. Numbers on branches indicate bootstrap supports. Branch lengths are proportional to the number of nucleotide substitutions per aligned site. The scale bars correspond to 0.01 (A,B) or 0.001 (C) substitutions per alignment position.

Figure 2

Comparison of consensus amino acid sequences of gH_a and gH_b of RRV. Identical residues are indicated with dots. Gaps in the sequence are indicated by dashes. Shading indicates variable positions. The sequences were aligned using the Mafft program with default parameters. The putative membrane-spanning domain is underlined.

Figure 3

Pairwise comparison of amino acid and nucleotide differences in selected RRV reading frames. A) gH; B) gL; C) gB; D) R1. Numbers above the black boxes are the numbers for pairwise amino acid differences. Numbers below the black boxes are the numbers for pairwise nucleotide differences.

Figure 3

Pairwise comparison of amino acid and nucleotide differences in selected RRV reading frames. A) gH; B) gL; C) gB; D) R1. Numbers above the black boxes are the numbers for pairwise amino acid differences. Numbers below the black boxes are the numbers for pairwise nucleotide differences.

Figure 3

Pairwise comparison of amino acid and nucleotide differences in selected RRV reading frames. A) gH; B) gL; C) gB; D) R1. Numbers above the black boxes are the numbers for pairwise amino acid differences. Numbers below the black boxes are the numbers for pairwise nucleotide differences.

Figure 3

Pairwise comparison of amino acid and nucleotide differences in selected RRV reading frames. A) gH; B) gL; C) gB; D) R1. Numbers above the black boxes are the numbers for pairwise amino acid differences. Numbers below the black boxes are the numbers for pairwise nucleotide differences.

Figure 4

Comparison of consensus amino acid sequences of gL_a and gL_b of RRV. Identical residues are indicated with dots. Gaps in the sequence are indicated by dashes. Shading indicates variable positions. The sequences were aligned using the Mafft program with default parameters.

Figure 5

Interaction of gH_a with gL_a and gL_b. RRV gH_a, gL_a, and gL_b were transiently expressed in HEK 293T cells. RRV ORF57 was included in all transfections to allow expression of the glycoproteins. The expression of each gene in whole cell lysates was evaluated by immunoblot (IB) analysis using anti-myc (gH_a) or anti-v5 (gL_a, gL_b, and ORF57) antibodies. Anti-myc antibody was used for immunoprecipitation (IP) of gH_a protein. Co-immunoprecipitated gL_a or gL_b protein was detected using anti-v5 antibody.

Figure 6

Pairwise comparison of amino acid and nucleotide differences in selected KSHV reading frames. A) gH; B) gL; C) gB. Numbers above the black boxes are the numbers for pairwise amino acid differences. Numbers below the black boxes are the numbers for pairwise nucleotide differences.

Figure 7

Comparison of consensus amino acid sequences of gB_a and gB_b of RRV. Identical residues are indicated with dots. Gaps in the sequence are indicated by dashes. Shading indicates variable positions. The sequences were aligned using the Mafft program with default parameters. The putative membrane-spanning domain is underlined.