Sequence analysis of the matrix protein gene of human parainfluenza virus type 3: extensive sequence homology among paramyxoviruses.

The sequences of the human parainfluenza virus type 3 (PIV3) matrix (M) mRNA [1150 nucleotides exclusive of poly(A)] and predicted M protein (353 amino acids) were determined by sequence analysis of cloned cDNA and viral genomic RNA. The gene-end sequence of the M gene differed from the semi-conserved gene-end sequence of the other PIV3 genes by an apparent insertion of eight nucleotides. The PIV3 M protein shared high sequence homology with Sendai virus and moderate homology with measles virus and canine distemper virus. Statistical analysis of the available sequences showed that the M protein was the most highly conserved parainfluenza viral protein.