A nuclear factor that binds purine-rich, single-stranded oligonucleotides derived from S1-sensitive elements upstream of the CFTR gene and the MUC1 gene

Hollingsworth, Michael A.; Closken, Christina; Harris, Ann; McDonald, Claudia D.; Pahwa, G. S.; Maher, L. James

doi:10.1093/nar/22.7.1138

Cited by 35 publications

(43 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cellular Fractionation-Preparation of membrane/cytoplasmic extracts and nuclear extracts was as described previously (33)(34)(35). Panc-1 and S2-013 cells were cultured on 225-cm 2 flasks to 90% confluence.…”

Section: Methodsmentioning

confidence: 99%

Nuclear Association of the Cytoplasmic Tail of MUC1 and β-Catenin

Wen

Caffrey

Wheelock

et al. 2003

Journal of Biological Chemistry

Self Cite

163

166

View full text Add to dashboard Cite

MUC1, an integral membrane mucin associated with the metastatic phenotype, is overexpressed by most human carcinoma cells. The MUC1 cytoplasmic tail (CT) is postulated to function in morphogenetic signal transduction via interactions with Grb2/Sos, c-Src, and ␤-catenin. We investigated intracellular trafficking of the MUC1 CT, using epitope-tagged constructs that were overexpressed in human pancreatic cancer cell lines S2-013 and Panc-1. The MUC1 CT was detected at the inner cell surface, in the cytosol, and in the nucleus of cells overexpressing MUC1. Fragments of the MUC1 CT were associated with ␤-catenin in both cytoplasm and nuclei. Overexpression of MUC1 increased steady state levels of nuclear ␤-catenin but decreased nuclear levels of plakoglobin (␥-catenin). There was no detectable association between plakoglobin and the MUC1 CT. Coimmunoprecipitation experiments revealed that the cytoplasmic and nuclear association of MUC1 CT and ␤-catenin was not affected by disruption of Ca 2؉ -dependent intercellular cadherin interactions. These results demonstrate nuclear localization of fragments of MUC1 CT in association with ␤-catenin and raise the possibility that overexpression of the MUC1 CT stabilizes ␤-catenin and enhances levels of nuclear ␤-catenin during disruption of cadherin-mediated cell-cell adhesion.Human MUC1 is a large, type I transmembrane protein normally expressed on the apical surface of ductal epithelia (1). Full-length MUC1 is synthesized as a single polypeptide chain, which undergoes an early proteolytic cleavage (probably in the endoplasmic reticulum) creating two subunits that remain associated during its post-translational processing and transport to the cell surface (2). The larger of the two fragments contains most of the extracellular domain, including the signal sequence and a tandem repeat domain (3-5). The smaller subunit contains a short extracellular domain, transmembrane domain, and cytoplasmic tail (CT), 1 which are highly conserved across species (88% identity with murine transmembrane and CT sequence) (6). The function of MUC1 is partially elucidated for normal and transformed cells. The extracellular fragment plays a significant role in configuring the adhesive and antiadhesive properties of cells and is believed to contribute to the establishment of molecular structures that protect the cell surface in the relatively harsh environment encountered by different ductal epithelia (7). However, the function of the intracellular portion of the MUC1 cytoplasmic tail (CT) is not known. Indirect evidence suggests that the MUC1 CT is involved in signal transduction, as it contains potential docking sites for Grb2/Sos and ␤-catenin, and can be phosphorylated by GSK-3␤, c-Src, EGFR, and PKC-␦ (7-16). This, together with the general transmembrane structure of the MUC1 molecule, suggests a potential role in morphogenetic signaling; however, little is known about mechanisms by which the MUC1 CT functions in this capacity, and nothing has been reported with regard to the relationship between...

show abstract

Section: Methodsmentioning

confidence: 99%

Nuclear Association of the Cytoplasmic Tail of MUC1 and β-Catenin

Wen

Caffrey

Wheelock

et al. 2003

Journal of Biological Chemistry

Self Cite

163

166

View full text Add to dashboard Cite

show abstract

“…Nuclear extracts were prepared from cell lines and DNase I footprinting was performed as descibed previously [20,35].…”

Section: Dnase I Footprinting In Vitromentioning

confidence: 99%

Analysis of DNase-I-hypersensitive sites at the 3′ end of the cystic fibrosis transmembrane conductance regulator gene (CFTR)

Nuthall

Moulin

Huxley

et al. 1999

Biochemical Journal

Self Cite

View full text Add to dashboard Cite

The cystic fibrosis transmembrane conductance regulator gene (CFTR) exhibits a complex pattern of expression that shows temporal and spatial regulation, although the control mechanisms are not fully known. We have mapped DNase-I-hypersensitive sites (DHSs) flanking the CFTR gene with the aim of identifying potential regulatory elements. We previously characterized DHSs at -79.5 and -20.9 kb with respect to the CFTR translational start site and a regulatory element in the first intron of the gene at 185+10 kb. We have now mapped five DHSs lying 3′ to the CFTR gene at 4574+5.4, +6.8, +7.0, +7.4 and +15.6 kb that show some degree of tissue specificity. The DHSs are seen in chromatin extracted from human primary epithelial cells and cell lines; the presence of the +15.6 kb site is tissue-specific in transgenic mice carrying a human CFTR yeast artificial chromosome. Further analysis of the 4574+15.6 kb DHS implicates the involvement of CCAAT-enhancer-binding protein (C/EBP), cAMP-response-element-binding protein (CREB)/activating transcription factor (ATF) and activator protein 1 (AP-1) family transcription factors at this regulatory element.

show abstract

“…As shown for other sequences (including our previous studies of shorter R/Y sequences from the CFTR and MUC1 promoters), such elements may adopt non-B DNA structures of unknown significance under certain in vitro conditions (11)(12)(13). The R/Y sequences near CFTR and MUC1 are similar to that near MT-I in that they display imperfect mirror symmetry consistent with the potential for isomerization to imperfect triplex (H-DNA) structures (12,13). The MT-I R/Y sequence contains no single plane of extensive mirror symmetry, but contains several imperfect purine/pyrimidine mirror repeats (PMRs) within it.…”

Section: Introductionmentioning

confidence: 57%

“…In previous experiments we have employed low resolution S1 nuclease sensitivity to demonstrate unusual structures in DNA sequences cloned from the CFTR and MUC1 gene promoters (12,13). These studies demonstrated that supercoiled (but not linearized) plasmids containing the PMR from these gene promoters displayed S1 nuclease sensitivity mapping in the region of the PMR.…”

Section: Resultsmentioning

confidence: 99%