Am. Mccutcheon et al., Mammalian reovirus M3 gene sequences and conservation of coiled-coil motifs near the carboxyl terminus of the mu NS protein, VIROLOGY, 264(1), 1999, pp. 16-24
Nucleotide sequences of the mammalian orthoreovirus (reovirus) type 1 Lang
and type 2 Jones M3 gene segments were newly determined. The nucleotide seq
uence of the reovirus type 3 Dearing M3 segment also was determined to comp
are with a previously reported M3 sequence for that isolate. Comparisons sh
owed Lang and Dearing M3 to be more closely related than either was to Jone
s M3, consistent with previous findings for other reovirus gene segments. T
he mu NS protein sequences deduced from each M3 segment were shown to be re
lated in a similar pattern as the respective nucleotide sequences and to co
ntain several regions of greater or less than average variability among the
three isolates. Identification of conserved methionine codons near the 5'
ends of the Lang, Jones, and Dearing M3 plus strands lent support: to the h
ypothesis that mu NSC, a smaller protein also encoded by M3, arises by tran
slation initiation from a downstream methionine codon within the same open
reading frame as mu NS. Other analyses of the deduced protein sequences ind
icated that regions within the carboxyl-terminal third of mu NS and mu NSC
from each isolate have a propensity to form alpha-helical coiled coils, mos
t likely coiled-coil dimers. The new sequences will augment further studies
on mu NS and mu NSC structure and function. (C) 1999 Academic Press.