engleski

HSV-1 miR-H1 arise from short transcripts upstream of the LAT promoter

Herpes simplex virus 1 is an important human pathogen and frequently used model to study basic biology of neurons. HSV-1 has two distinct stages of infection, productive and latent infection. During both phases HSV-1 is expressing a number of miRNAs, small RNA molecules that regulate expression of viral and cellular genes. In our study, we focus on miRNA-H1, a virus miRNA abundantly expressed only during productive phase of infection. The transcript that gives rise to miR-H1, its promoter, regulation of its expression or its function are not known, however abundance of miR-H1 during the productive phase of infection indicates an important role in that phase. To reveal the primary transcript of miR-H1 we analyzed RNA from cells infected with HSV-1 using both Northern blot and rapid amplification of cDNA ends (RACE). In our Northern blot analysis we detected a set of short transcripts (0.4 - 0.7 kb long) arising from the region upstream of the LAT promoter, which might represent the origin of miRH1. In addition we determined the transcriptional start and terminus sites of these transcripts. Interestingly, using the PePPER software, we identified a promoter upstream and in the vicinity of the transcriptional start site of the largest (0.7 kb) transcript in the region. To confirm experimentally the prediction of the promoter and define its role in miR H1 expression, we have generated mutant viruses with a transcriptional termination signal sequence inserted downstream or upstream of the putative promoter and we are currently analyzing these viruses.

HSV-1, miRNA, primary transcript, promoter

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