REARRANGEMENT OF THE VP6 GENE OF A GROUP-A ROTAVIRUS IN COMBINATION WITH A POINT MUTATION AFFECTING TRIMER STABILITY

A group A rotavirus isolated from a lamb with diarrhea in Qinhai provi nce, China, was serially passaged in fetal calf kidney cells. In passa ge 96, rearrangements of RNA segments 5 and 6 of the viral genome were found. Here we report the nucleotide and predicted amino acid sequenc es of normal and rearranged RNA 6, coding for the major inner capsid p rotein VP6. In comparison with the normal gene (N6), the rearranged RN A 6 (R6) contained the normal open reading frame followed by a 473-nuc leotide (nt) duplication of the gene beginning 23 nt after the termina tion codon. The duplicated region starts at nt 768 and runs through to the 3' end of the gene. In accordance with the nucleotide sequence of the rearranged RNA 6, a normal-length VP6 product was found in cells infected with the mutant. However, a single-amino-acid change from pro line to glutamine at position 309 slightly affected the electrophoreti c mobility of the VP6 monomer of the R6 mutant and reduced the stabili ty of VP6 trimers on gels and at low pH values compared with the norma l gene product. The degree of relatedness of VP6 of the Chinese lamb r otavirus Lp14 to those of other group A rotaviruses was determined.