PCPV is a member of the parapoxvirus genus the type specis of which is Orf virus (ORFV). PCPV is maintained in cattle, while ORFV is maintained in sheep and goats and both infect humans. Recently, a homolog of the vascular endothelial growth factor (VEGF) has been identified in the VR634 pseudocowpoxvirus (PCPV genome). The relatedness between PCPV VR634 VEGF and ORFV NZ7 VEGF raised the possibility that ORFV NZ7 strain is a natural recombinant between strains of ORFV and PCPV and that the DNA segment spanning the VEGF gene of PRFV NZ7 is derived from PCPV. In our study, the VEGF genes of two PCPV field strains (1303/05 and 380/06) recently isolated in Italy, were characterised. Phylogenetic analysis was carried out using the maximum likelihood approach and a variety of statistical analyses regarding genetic differentiation and gene flow were performed with DNASP version 4.10. To screen for recombination, we employed two preliminary detection programs: Single Breackpoint recombination and Genetic Algorithms for Recombination Detection, both implemented in Datamonkey. A breakpoint of recombination has been identified at nucleotide position 237 of NZ-2 gene corresponding to a conserved codon encoding for CYS in all the viral variants indicating that recombination may occur at this site while DNASP and statistical tests support the hypotesis that PCPV 1303 and 380 VEGFs differentiated from NZ-2 variants. PCPV amino acid sequences were compared with other viral VEGFs using Clustal W. A 51% and 41,6% identity values were computed with the NZ-2 and VR634 variants, respectively. The secondary and tertiary structure analysis was performed with PSIPRED and Homology Modelling, indicating the conservation of the functional motifs and signature. The characterisation of the C-terminal has been performed to compare the amino acid residues involved in the interaction with NP-1 and R1 receptors. C-terminal peptides identified in the PCPV 1303 and 380 VEGF-variants suggest a low affinity with the receptor NP-1, while the presence of few glycosilation sites may lead to the activation of R1 which mediates monocyte migration. Taken together our results provide new insights into interspecies recombination between bovine and sheep parapoxviruses and on the role of VEGF in normal and pathological conditions.
Comparative analysis of pseudocowpoxvirus VEGF genes: evidence for interspecies recombination and different pattern of receptor activation
VACCARI, FRANCESCA;BATTILANI, MARA;TASCO, GIANLUCA;CASADIO, RITA;SCAGLIARINI, ALESSANDRA
2010
Abstract
PCPV is a member of the parapoxvirus genus the type specis of which is Orf virus (ORFV). PCPV is maintained in cattle, while ORFV is maintained in sheep and goats and both infect humans. Recently, a homolog of the vascular endothelial growth factor (VEGF) has been identified in the VR634 pseudocowpoxvirus (PCPV genome). The relatedness between PCPV VR634 VEGF and ORFV NZ7 VEGF raised the possibility that ORFV NZ7 strain is a natural recombinant between strains of ORFV and PCPV and that the DNA segment spanning the VEGF gene of PRFV NZ7 is derived from PCPV. In our study, the VEGF genes of two PCPV field strains (1303/05 and 380/06) recently isolated in Italy, were characterised. Phylogenetic analysis was carried out using the maximum likelihood approach and a variety of statistical analyses regarding genetic differentiation and gene flow were performed with DNASP version 4.10. To screen for recombination, we employed two preliminary detection programs: Single Breackpoint recombination and Genetic Algorithms for Recombination Detection, both implemented in Datamonkey. A breakpoint of recombination has been identified at nucleotide position 237 of NZ-2 gene corresponding to a conserved codon encoding for CYS in all the viral variants indicating that recombination may occur at this site while DNASP and statistical tests support the hypotesis that PCPV 1303 and 380 VEGFs differentiated from NZ-2 variants. PCPV amino acid sequences were compared with other viral VEGFs using Clustal W. A 51% and 41,6% identity values were computed with the NZ-2 and VR634 variants, respectively. The secondary and tertiary structure analysis was performed with PSIPRED and Homology Modelling, indicating the conservation of the functional motifs and signature. The characterisation of the C-terminal has been performed to compare the amino acid residues involved in the interaction with NP-1 and R1 receptors. C-terminal peptides identified in the PCPV 1303 and 380 VEGF-variants suggest a low affinity with the receptor NP-1, while the presence of few glycosilation sites may lead to the activation of R1 which mediates monocyte migration. Taken together our results provide new insights into interspecies recombination between bovine and sheep parapoxviruses and on the role of VEGF in normal and pathological conditions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
