EXPRESSION OF THE AMINO-ACID DIMORPHISM IN THE SMALL MYELIN-ASSOCIATED GLYCOPROTEIN CYTOPLASMIC DOMAIN IN RAT PERIPHERAL-NERVES DURING POSTNATAL-DEVELOPMENT
P. Kursula et al., EXPRESSION OF THE AMINO-ACID DIMORPHISM IN THE SMALL MYELIN-ASSOCIATED GLYCOPROTEIN CYTOPLASMIC DOMAIN IN RAT PERIPHERAL-NERVES DURING POSTNATAL-DEVELOPMENT, Molecular brain research, 54(2), 1998, pp. 252-261
The myelin-associated glycoprotein (MAG) is one of the proteins expres
sed during the period of myelin formation and is believed to play a ma
jor role in the initiation of myelination. It exists as two differenti
ally expressed isoforms, L- and S-MAG, that are generated by alternati
ve mRNA splicing. A nucleotide dimorphism at the mRNA level resulting
in an Arg/Pro dimorphism in the cytoplasmic tail of the S-MAG protein
has previously been detected in the rat brain. In this study, we show
that this dimorphism is detectable in the rat peripheral nervous syste
m. We propose an allelic origin for the dimorphism and demonstrate the
differential expression of the S-MAG alleles in the sciatic nerves of
heterozygous rats during the period of active myelination. We also pr
esent data on the properties of the two S-MAG cytoplasmic domains prod
uced as GST fusion proteins. The importance of this differentially exp
ressed amino acid dimorphism is discussed, taking into account both it
s probable effect on the S-MAG cytoplasmic domain function and its sig
nificance in functional and structural studies concerning the S-MAG pr
otein. (C) 1998 Elsevier Science B.V.