Comparison of the deduced matrix and fusion protein sequences of equine morbillivirus with cognate genes of the Paramyxoviridae.

The research paper deals primarily with the genetic analysis of the equine morbillivirus (EMV), comparing the nucleotide sequences of its matrix protein and fusion protein with the cognate genes found in the Paramyxoviridae family.

Decoding the Equine Morbillivirus

• The research begins by decoding the genetic structure of the EMV’s matrix protein. This gene was found to be 1062 nucleotides long and to encode a deduced protein which had a molecular weight (M(r)) of 40148 and a net charge of +19 at neutral pH.
• The matrix protein gene was separated from the P and F genes by intercistronic regions of 546 and 469 nucleotides respectively. This suggests distinct roles for these proteins in the replication and transcription of the EMV.
• In addition, the nucleotide sequence for the F protein was identified to be 1641 nucleotides long and to code for a deduced protein of 546 amino acids, with an M(r) of 60,447 and a charge of +4 at neutral pH. The partial sequence information for the P/V proteins was also determined.

Comparing with the Paramyxoviridae

• When the sequences of the M, P, and F proteins were compared, greater homology was found between the EMV and known members of the morbillivirus genus than with other members of the Paramyxoviridae.
• The homology was stronger in the central part of the fusion protein, the C-terminal part of the matrix protein, and at certain sites within the P protein.
• Through phylogenetic analyses, the researchers inferred that the EMV can be considered a distant relative of the morbillivirus genus.

Identifying Shared Genetic Markers

• The researchers identified an 18 nucleotide-long conserved sequence, assumed to be the transcriptional editing site, within the P gene of the EMV.
• A single nucleotide insertion within this site resulted in the creation of a C-terminus of a V-like, cysteine-rich protein.
• Finally, a conserved ‘CTT’ intergenic region, believed to be the transcription termination and polyadenylation signal, was identified between the P-M-F genes.
• The presence of these markers, along with the overall homology of sequences, strongly suggests that EMV is indeed a member of the morbillivirus genus.