Viral microRNA Flashcards
(13 cards)
What are viral microRNAs?
miRNAs encoded within viral genomes
Most commonly found in the Herpesviridae family, with some evidence in Polyomaviridae and Adenoviridae.
Which family of viruses most commonly contains viral miRNA?
Herpesviridae
Some evidence also exists for Polyomaviridae and Adenoviridae.
What happens to RNA viruses with a miRNA in their genome?
Processed by Drosha, inactivating the genome
Limited evidence exists for the presence of an HIV-1 miRNA.
What are the two modes of action for viral microRNA?
trans and cis
Trans-regulation targets host genes, while cis-regulation targets viral genes.
What is trans-regulation in viral microRNA?
Targets host genes and silences genes detrimental to viral replication
Evidence also suggests regulation of viral genes that stimulate immunity.
What is cis-regulation in viral microRNA?
Targets viral genes and allows the virus to enter a latent state
Evidence exists for regulation of host genes involved in viral latency.
What is an example of trans-regulation by viral miRNA?
HCMV miRNA miR-UL112-1 targets MICB
MICB is recognized by the NKG2D receptor on NK cells and CD8+ T-cells.
Which viruses regulate MICB expression through miRNA?
EBV and KSHV
EBV miR-BART2-5p and KSHV miR-K12-7 similarly regulate MICB expression.
How does KSHV viral miRNA affect pro-inflammatory cytokines?
Reduces pro-inflammatory cytokines
Examples include miR-K12-11 targeting IKKε and miR-K10a targeting IL-8 and MCP-1.
What is the role of miR-H2-3p and miR-H6 in herpes simplex virus-1?
Inhibits early viral replication events
They inhibit ICP0 and ICP4, which are required for early viral transcription.
What is the function of ICP0 and ICP4 in viral replication?
Required for early viral replication events
Ensures correct initiation of viral transcription.
True or False: Viral microRNA can only act in cis.
False
Viral microRNA can act in both trans and cis.
Fill in the blank: Viral miRNA can act in _____ or in _____ regulation.
trans, cis
