MOLECULAR-CLONING OF A NOVEL HIGH-MOLECULAR-WEIGHT MUCIN (MG1) FROM HUMAN SUBLINGUAL GLAND

A human sublingual gland cDNA library was screened with a polyclonal a ntiserum against deglycosylated MG1 and a positive clone, pSM2-1, was isolated which codes for 196 amino acids in the carboxyl-terminal regi on of this mucin. This region is cysteine-rich and contains a C2-like domain upstream of the extreme carboxyl-terminal domain in which the a rrangement of cysteines is nearly identical to that in human von Wille brand factor, human intestinal mucin MUC2, human tracheobronchial muci n MUC5 and porcine and bovine submaxillary gland mucins. Northern anal yses with pSM2-1 showed MG1 transcripts are abundant in sublingual gla nd and barely detectable in submandibular gland. This study provides t he first primary sequence data on human salivary mucin MG1 and the sig nificance of the results is discussed with respect to the biosynthesis and differential expression of MG1 in human salivary glands. (C) 1995 Academic Press. Inc.