Investigators led by Eain Murphy of Cleveland Clinic have identified a viral microRNA (miRNA) for HHV-6A, named miR-U86, that targets the HHV-6A intermediate early gene U86. They also found that the target of this viral encoded miRNA is a critical transcriptional activator of HHV-6A, suggesting that it is involved in auto-regulation.
The group sequenced all of the small RNAs from HHV-6A infected cells and found a number of candidates that differed from those previously identified for closely related HHV-6B, reinforcing the finding that these are two distinct viruses.
“Work from my lab and others suggest that this form of regulation appears to be conserved across the herpesviruses and may be critical for maintaining latency, of which herpesviruses are the masters,” said Murphy. His future plans include determining if the absence of these miRNAs result in an infection that can not undergo latency. Another question he will study is whether these miRNAs may be involved in silencing chromosomally integrated HHV-6.