Santanu Chattopadhyay, Frank Esper and Amiya K. Banerjee
from: The Biology of Paramyxoviruses (Edited by: Siba K. Samal). Caister Academic Press, U.K. (2011)
Parainfluenza viruses (PIVs) include several members of the Paramyxoviridae family of the Mononegavirales order ranging from Respirovirus, Avulavirus and Rubulavirus genera. These group of viruses consist of several species that causes upper and lower respiratory illness in humans, especially among children and in a variety of animals. These medium sized, pleomorphic, enveloped viruses attach to the host cells' membranes and get internalized at neutral pH with the help of Hemagglutinin-Nuraminidase (HN) and Fusion (F) - the two surface glycoproteins. Inside the cytoplasm, the ~15 Kb non-segmented negative sense RNA (NNS) genomes that are encapsidated by the viral nucleocapsid protein (N) are transcribed and replicated by the associated viral polymerase heterocomplex - the large protein (L) and the phosphoprotein (P). The newly replicated RNA genomes are concomitantly encapsidated by the N protein and with the help of the matrix proteins (M), assemble and bud out as mature virions containing the viral glycoproteins and the polymerase along with the host cell membrane envelope. The P gene of PIVs characteristically encodes several accessory proteins, viz C, V, W, D, which are expressed by mRNA editing or alternative translation mechanisms. Despite significant ongoing efforts, no suitable vaccine or antiviral compounds are available to date against these clinically and economically important viruses read more ...