Sequence and organization of the left multigene family 110 region of the Vero-adapted L60V strain of African swine fever virus.

Sequencing of the left variable region of the L60V Vero cell-adapted strain of African swine fever virus (ASFV) showed the presence of three genes belonging to multigene family 110 (MGF110) and of a fourth unrelated gene. This gene was separated from the MGF110 genes by a region rich in direct repeats. The first MGF110 gene, V1L, with 104 codons, was only moderately related to the other two, W1L and W2L, with 124 and 80 codons, respectively. These two genes were closely related, W2L being a truncated duplication of W1L. Homology matrix analysis of the sequence against itself showed the existence of a repeated block corresponding to the central conserved domain of the three genes, flanked by two other repeated blocks in W1L and W2L. The comparison of the organization of the left variable region of ASFV L60V with that of field isolates and other adapted viruses revealed that adaptation of unrelated viruses resulted in similar large deletions that map, in their right boundaries, exactly at the same positions in the intergenic repeat-rich region.