Figure 1 (Right) Negative contrast electron micrographs of intact parainfluenza virus 5 (PIV5, previously known as simian virus 5 [SV5]) particles (genus Rubulavirus) (top) and the PIV5 nucleocapsid after detergent lysis of virions (bottom) (courtesy of G.P. Leser and R.A. Lamb). The bars represent 100 nm. (Left top and bottom) Schematic diagrams of PIV5 particles in cross-section (N) (formerly NP), nucleocapsid; P, phospho-protein; L, large polymerase protein; V, cysteine rich protein that shares its N-terminus with P sequence and for PIV5 is found in virions; M, matrix or membrane protein; F, fusion protein; HN, hemagglutinin-neuraminidase; SH, small hydrophobic protein). (Adapted from Kingsbury, D.W. (1990). Paramyxoviridae: the viruses and their replication. In: Virology, 2nd edn (B.N. Fields and D.M. Knipe, Eds.), Raven Press, New York; and from Scheid, H. (1987). In: Animal Virus Structure (M.V. Nermut, and A.C. Steven, Eds.), Elsevier, Amsterdam; with permission.)
Figure 2 Maps of genomic RNAs (3′-to-5′) of viruses in the family Paramyxoviridae. Viruses were selected from the seven established genera as well as a group of unassigned viruses, which significantly increased the genetic diversity of the family. Each box represents a separately encoded mRNA; multiple distinct ORFs within a single mRNA are indicated by slashes. The M2 mRNA of members of subfamily Pneumovirinae has two overlapping ORFs, M2-1 and M2-2 (not shown). The lengths of the boxes are approximately to scale although the intervening or preceding sequences are not to scale. The D ORF present in the respirovirus HPIV3 is not shown. Certain viruses give rise to additional proteins by the utilization of secondary translational start sites within some of the ORFs: these are not shown. In HPIV1 and HPIV3 of the genus Respirovirus the V ORF may be a non-expressed relic. In the genus Rubulavirus some species lack the SH gene. In the genus Pneumovirus, HRSV has a transcriptional overlap at M2 and L (staggered boxes). There are conserved trinucleotides that serve as intergenic sequences for the respiroviruses, henipaviruses and morbilliviruses. For rubulaviruses, avulaviruses, pneumoviruses and meta-pneumoviruses, the intergenic sequences are variable (1–190 nt long). In the group of unassigned new viruses, all of them have a 3-nt intergenic region similar to those observed in the genera Morbillivirus, Respirovirus and Henipavirus. However, the genome sizes of these new viruses vary significantly from 15,378 nt to 19,212 nt. There are also novel genes present in these viruses (such as the U gene in FedPV and the TM gene in BeiPV) which have never been seen in previously known paramyxoviruses.
Figure 3 Phylogenetic analysis of the L proteins of members of the family Paramyxoviridae. Phylogenetic analysis using MEGA4.1 was performed on the aa sequence of L proteins from various members of the family Paramyxoviridae. The tree shown was based on maximum parsimony; however, analysis of the same data using maximun likelihood produced a tree with nearly identical topology (data not shown).