Popular Posts

Translate

Hepatitis E


This virus , which causes enteric non-A, non-B hepatitis, seems to be related to the Caliciviruses but its classification is undecided since the genome organization is not the same as that of the Caliciviridae. 

In sequence, HEV is more similar to rubella which is a Togavirus than to any Calicivirus. HEV is a small (approximately 34nm), round, icosahedral, positive strand RNA virus that does not have an envelope. It has a rather smooth surface but not as smooth a HAV. The genome has a poly A tract and is capped at the 5’ end. There are three open reading frames that overlap; each is in a different coding frame. Based on sequence motifs, open reading frame 1 (ORF1) appears to have several enzymic activities. These may be involved in RNA capping, proteolysis and an RNA-dependent RNA polymerase activity. 

ORF2 is the structural protein and may be glycosylated. It appears to have a signal sequence suggesting that its encoded protein may enter the endoplasmic reticulum. The third ORF codes for a phosphoprotein of unknown function that interacts with the host cell’s cytoskeleton. Not much is known about HEV replication but it is likely that the positive strand RNA is copied to a negative strand intermediate by a viral polymerase.

tags:hepatitis E,which causes enteric non-A, non-B hepatitis,Not much is known about HEV replication ,These may be involved in RNA capping,hepatitis E,

Popular Posts