Transcription and Translation of Sendai Virus Hemagglutinin-neuraminidase (HN) in Mammalian Cells.

Sendai virus hemagglutinin-neuraminidase was expressed in COS-7 cells. LLCMK(2) cells were transfected with expression plasmids harboring HN, namely pJH3, pJH4 or pJH7, and were passaged conti-nuously under the presence of hygromycin or puromycin to get antibiotic-resistant clones, which had HN gene integrated into genomes. S1 nuclease assay indicated that large quantity of HN mRNA was transcribed but indirect-immunofluorescence and immunoprecipitation demonstrated that there was little HN protein expressed on cell surface and inside cells, in contrast with the Sendai virus persistent-infected LLCMK(2) cells that expressed largely HN protein. Therefore, not every transcription resulted in translation. It also suggests that some virus factors may positively regulate transcription and translation of HN mRNA.