Thus all three possible reading frames are read. IN the case of aprainfluenza 3, a fourth protein D, is translated by insertion of two nontemplated G residues. As the concentration of N proteins builds up in the cells, these molecules are beleived to associate either with the transcriptase or with nascent plus strantds, preventing polyadenylation, termination and reinititation, thus switching to the replication mode in which full length plus strands are made. These in turn serve as templates fro RNA replication. Newly synthesised minus strands associate with N protein and transcriptase to produce nucleocapsids, which eventually associate with M protein at the apical surface of the membrane into which HN or F proteins have migrated, casuing cells to fuse with adjacent uninfected cells.
Infection occurs via the respiratory tract.
Transported by macrophages to lymph nodes. About six days after infection viremia occurs. Virions seede to all the epithelial surfaces of the body. ABout 9 days after exposure abrubt onset of illness with cough, running nose, and inflamed conjunctivae. Immune repsonse contribute to respiratory damage., malaise and fever.