Chromosomal localization of a human mucin gene (MUC8) and cloning of the cDNA corresponding to the carboxy terminus.

Abstract

A partial cDNA (pAM1) encoding a major airway mucin glycoprotein with novel tandem repetitive sequence has recently been cloned (Shankar, V., M. S. Gilmore, R. C. Elkins, and G. P. Sachdev. 1994. Biochem. J. 300:295-298). In this article, we report additional new sequence derived by 3'-rapid amplification of cDNA ends technique. The sequence corresponds to a stop codon, 3'-untranslated region of 458 bp, a polyadenylation signal, and poly A+ tail, and represents the extreme carboxy terminus of MUC8. A plasmid construct (pAM3) in pBluescript was generated by in-frame ligation of pAM1 to the 479-bp 3'UTR of MUC8. A 5'-end 325-bp fragment of this cDNA subcloned into the protein fusion and expression vector pET28b(+) was used to generate fusion protein under the control of T7 promoter. The purified fusion protein as well as synthetic peptide corresponding to the MUC8 repeat sequence (TSCPRPLQEGTPGS) were used to raise polyclonal antibodies in rabbits. The antiserum to the fusion protein and to the synthetic peptide reacted with the deglycosylated major tracheobronchial mucin. Immunohistochemical studies using the above antibodies localized the MUC8 protein product to submucosal glands in human tracheal epithelium. Furthermore, the gene from which this cDNA is derived, was mapped to chromosome 12 using DNA from a panel of human-mouse somatic cell hybrids. Fluorescence in situ hybridization was used to assign the regional localization to 12q24.3. Since the eight known human mucin genes map to other chromosomes, we have named this gene MUC8, in accordance with mucin gene nomenclature.

Regulation of Airway Mucin Gene Expression

“…Mutagenesis experiments further elucidated that the AP-1 sites are important for MUC7's basal expression whereas NF-κB is important for the responsiveness of MUC7 to TNF-α (136). MUC8 is a secreted mucin that is also primarily localized to the submucosal glands of the trachea (137). Its expression, however, does not appear to be related to differentiation (130).…”

Expression of Mucins in Mucoid Otitis Media

“…Possible candidates include MUC4, MUC5AC, MUC5B, and MUC6-8 (Gendler and Spicer 1995;Kim and Gum 1995;Rose and Gendler 1997;Shankar et al 1997). Therefore, various mucin cDNA probes and antibodies were used for the characterization and identification of mucins in MOM.…”

Interleukin-1β and Tumor Necrosis Factor-α Induce MUC5AC Overexpression through a Mechanism Involving ERK/p38 Mitogen-activated Protein Kinases-MSK1-CREB Activation in Human Airway Epithelial Cells

“…Eighteen types of mucin genes have been discovered to date: MUC1 (5), MUC2 (6), MUC3 (7), MUC4 (8), MUC5AC (9), MUC5B (10), MUC6 (11), MUC7 (12), MUC8 (13), MUC9 (14), MUC10 (15), MUC11 (16), MUC12 (16), MUC13 (17), MUC15 (18), MUC16 (19), MUC17 (20), and MUC18 (21). Of these, MUC5AC and MUC5B are generally recognized to be the major airway mucins (22)(23)(24) because MUC5AC is highly expressed in the goblet cells of the human airway epithelium.…”