IDENTIFICATION OF A 42-KDA NUCLEAR FACTOR (NF1-MUC5B) FROM HT-29 MTX CELLS THAT BINDS TO THE 3'-REGION OF HUMAN MUCIN GENE MUC5B

MUC5B gene is one of the four human mucin genes mapped to chromosome 1 1p15. The identification of three potential Spl binding sites located between the tandem repeat and the 3' end of MUC5B suggests a possible regulatory role for this region. In this report we show by electrophor etic mobility shift assay that only one potential Spl binding site (NA U62) leads to a specific interaction with a nuclear factor from HT-29 MTX cells which does not exist in parental HT-29 cells. By using mutat ed versions of NAU62, an 18 mer sequence within this later was shown t o be directly involved in the interaction. The nuclear factor called N F1-MUC5B which binds to this element has a M(r) of 42000 and is not Sp 1. These results suggest that MUC5B contains a sequence in its 3' regi on that might act as a cis-element. This report opens the field of tra nscriptional regulation of human mucin genes encoding secreted mucins. (C) 1996 Academic Press, Inc.