DEGENERATE 87-BASE-PAIR TANDEM REPEATS CREATE HYDROPHILIC HYDROPHOBICALTERNATING DOMAINS IN HUMAN MUCIN PEPTIDES MAPPED TO 11P15

A human tracheobronchial lambdagt 11 cDNA library was screened using a ntiserum prepared against the deglycosylated protein backbone of human tracheobronchial mucins. Two cDNAs, designated JER 28 and 57, obtaine d from this immunoscreening, were used to isolate two other cDNA clone s, JUL 7 and JUL 10, from a human tracheobronchial lambdagt 10 cDNA li brary. These four clones (561, 1830, 1631 and 991 bp), which mapped to chromosome 11p15, were all found to contain degenerate 87-base-pair t andem repeats which encode non-repetitive peptides. Numerous deletions or insertions in all otherwise virtually perfect 87-base-pair tandem repeat create many shifts in reading frame which completely destroy th e repetitive peptide structure. The peptide is composed of alternate h ydrophobic and hydrophilic domains which probably differ in the extent to which they are glycosylated. The mRNAs are expressed both in the r espiratory and in the digestive tracts. These human mucin probes may b e important in assessing the abnormal mucins associated with inflammat ory diseases or carcinoma from human mucosae.