INSECT CELLS INFECTED WITH A RECOMBINANT BACULOVIRUS EXPRESS BOTH O-GLYCOSYLATED AND N-GLYCOSYLATED FORMS OF THE RAT GLYCOPROTEIN HORMONE ALPHA-SUBUNIT
R. Delahaye et al., INSECT CELLS INFECTED WITH A RECOMBINANT BACULOVIRUS EXPRESS BOTH O-GLYCOSYLATED AND N-GLYCOSYLATED FORMS OF THE RAT GLYCOPROTEIN HORMONE ALPHA-SUBUNIT, Journal of molecular endocrinology, 16(2), 1996, pp. 141-149
Glycoprotein hormones LH, FSH, TSH and chorionic gonadotrophin are het
erodimers composed of two non-covalently associated subunits, a common
alpha- and a specific beta-subunit. A recombinant baculovirus contain
ing a cDNA encoding the alpha-subunit of rat glycoprotein hormones was
constructed. Viral-infected cells expressed, 48 h post infection, 7-1
0 mg immunoreactive alpha-glycopolypeptide/6 x 10(8) cells, of which 6
5.6% was able to associate with native LH beta and formed a biological
ly active heterodimeric hormone that bound to testicular receptors. Th
e treatment with specific glycanases showed that the recombinant alpha
-subunit was produced as two differently glycosylated forms; an M(r) 2
3 000 form which contained exclusively N-linked carbohydrate units and
another of M(r) 25 000 which appeared to contain additional O-linked
carbohydrate. Data demonstrated that the alpha-subunit was expressed b
y insect cells in a manner similar to that by mammalian pituitary gona
dotropes producing both the N- and O-glycosylated forms although only
the N-glycosylated alpha-subunit is known to be capable of associating
with the beta-subunit.