Regulation of transglutaminase type I expression in squamous differentiating rabbit tracheal epithelial cells and human epidermal keratinocytes: effects of retinoic acid and phorbol esters.
In the present study we describe the full length cDNA sequence for rabbit transglutaminase type I as well as the sequence for a 2.9-kilobase (kb) promoter fragment of the gene. Transglutaminase type I mRNA expression was inhibited in squamous differentiating epithelia by retinoic acid (RA) in a dose-dependent (EC50 = 1-2 nM) and transcriptional manner. In human epidermal keratinocytes transglutaminase type I mRNA was induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment, and this induction could be inhibited by bryostatin 1. In contrast, TPA treatment inhibited the expression of c-myc mRNA. Bryostatin 1 but not RA could prevent this decrease in c-myc mRNA expression, indicating that transglutaminase type I mRNA expression was associated with differentiation and not growth arrest. An SP1 element was found within 50 base pairs 5' of the transcription initiation site. A TATA-like element (CATAAAC) was found but was not capable of activating transcription. In addition, putative response elements for C-MYC, Ker1/AP2, 2 AP1 sites, a CK-8-mer, and an AP2 site were present in the 2.9-kb fragment. Transfection of RbTE cells with the 2.9-kb fragment ligated to a promoterless luciferase vector resulted in 2.2-fold more luciferase expression in differentiated vs. undifferentiated cells. Furthermore, luciferase activity was induced 7.4-fold in human epidermal keratinocytes induced to differentiate with TPA. TPA-induced luciferase activity was inhibited by both bryostatin 1 and RA. No known RA response elements were identified in the promoter.(ABSTRACT TRUNCATED AT 250 WORDS)
Saunders
N A
NA
Cell Biology Section, National Institute of Environmental Health Sciences, National Institutes of Health Research Triangle Park, North Carolina 27709.
Bernacki
S H
SH
Vollberg
T M
TM
Jetten
A M
AM
D000595:Amino Acid Sequence; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001483:Base Sequence; D054713:Bryostatins; D002454:Cell Differentiation; D002478:Cells, Cultured; D004247:DNA / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004848:Epithelium / Q000201:enzymology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D015603:Keratinocytes / Q000201:enzymology*; D007783:Lactones / Q000494:pharmacology; D008156:Luciferases / Q000096:biosynthesis; D018942:Macrolides; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000737:chemistry; D011817:Rabbits; D012045:Regulatory Sequences, Nucleic Acid; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014132:Trachea / Q000166:cytology / Q000201:enzymology*; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D011503:Transglutaminases / Q000096:biosynthesis* / Q000235:genetics; D014212:Tretinoin / Q000494:pharmacology*
D000970:Antineoplastic Agents; D054713:Bryostatins; D007783:Lactones; D018942:Macrolides; D012333:RNA, Messenger; C046785:bryostatin 1; D014212:Tretinoin; D004247:DNA; D008156:Luciferases; D011503:Transglutaminases; D013755:Tetradecanoylphorbol Acetate