Fig. 6.

Schematic representation of Newcastle disease virus replication. Entry of the virus into the host cell system is mediated by the interaction of glycoproteins (F, HN) on viral surface and binding to sialic acid-containing compounds such as gangliosides and N-glycoproteins receptors on cell surface, resulting in fusion of the virus to host cells. The viral nucleocapsid is then pushed into the host cytoplasm where the negative sense viral RNA is transcribed to produce the structural mRNAs, with the help of virus associated RNA dependent RNA polymerase in a gradient fashion. The respective proteins are translated and folded using host cell machinery. Once a threshold of the first transcribed N mRNA is reached, the negative sense genomic RNA is converted to positive sense anti-genome template for the synthesis of new negative sense RNA genome. This newly formed genomic RNA is then wrapped in N, P and L proteins to form the nucleocapsid that is assembled with matrix and surface glycoproteins and released from the host cell.