Background: To determine the nucleotide sequence of noncoding regions of Measles virus strain Changchun-47 (CC-47) and to compare them with other measles virus for revealing some vaccine-related information.
Methods: Six overlapped fragments, that covers complete genome of CC-47 were amplified by using RT-PCR, all of the amplified fragments have been cloned and sequenced.
Results: Seven noncoding regions lie in the genome sequence of CC-47 separated by six structure genes. The noncoding regions of CC-47 contain 1791 nucleotides totally. Comparing of the noncoding regions of CC-47 with other wild type strains and five Edmonston-derived vaccine strains, four nucleotide substitutions were shared by nearly all vaccine strains. Two of these were in the genomic 3 terminal transcriptional control region: position 26 (U->G), 42 (U->G); the other were in the F mRNA 5 -untranslated region of M/F intergenic region. These site substitutions may influence the efficiency of mRNA synthesis, processing, and translation, as wel l as genome replication and encapsidation.
Conclusions: The nucleotide substitutions shared by different genotype measles virus vaccine strains may be related to virus growth in semipermissive cell or process of attenuation, which provide useful data for molecular epidemiology of measles virus. The nucleotide substitutions for attenuation were involved in several regions other than one definite region.