Fig. 3.

Schematic representation of the HMPV life cycle. After attachment of the virion to the plasma membrane, the viral and plasma membranes fuse, resulting in uncoating of the virion and release of the RNP (containing the negative-sense viral RNA) into the cytoplasm. After primary transcription, the genome is replicated to produce the antigenome. The antigenome is used to synthesize genomic RNA, which is used to produce additional antigenomes for incorporation into progeny virions or as a template for secondary transcription. After translation, M proteins and RNPs are transported intracellularly to the plasma membrane and the viral glycoproteins F (fusion), G (glycoprotein), and SH (small hydrophobic) are transported from the endoplasmic reticulum (ER) to the Golgi apparatus and then the plasma membrane. Finally, new virions are assembled and are subsequently released from the plasma membrane by a budding process.