Dominant and nondominant negative C-erbA beta 1 receptors associated with thyroid hormone resistance syndromes augment 12-O-tetradecanoyl-phorbol-13-acetate induction of the collagenase promoter and exhibit defective 3,5,3'-triiodothyronine-mediated repression.
C-erbA receptors and v-erbA have been shown to functionally interact with 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-inducible gene expression. These proteins enhance trans-activation by c-jun, and the c-erbA receptors in the presence of thyroid hormone repress TPA and c-jun induction of transcription. Also, v-erbA can abrogate T3-mediated repression. We have examined how dominant negative (S and CL) and nondominant negative (G-H) receptors cloned from various patients with thyroid hormone resistance syndromes affect expression of the collagenase promoter induced with TPA. The CL receptor (ARG315HIS mutation) has a 2-fold reduction in T3-binding affinity compared with human c-erbA beta 1 wild-type (WT) receptor, whereas the G-H receptor (ARG311HIS) and S receptor (deletion, THR codon 332) have T3-binding affinities reduced by 100-fold and greater than 100-fold, respectively. These mutant receptors were cotransfected with a collagenase promoter (-1200 to +63 base pairs) chloramphenicol acetyltransferase reporter gene (Col-CAT) into COS-7 cells. Levels of CAT reporter gene expression after transient transfection were determined in the presence or absence of 3-10 nM T3 and the presence or absence of 100 nM TPA. Unoccupied CL receptor and G-H and S receptors stimulated TPA-induced Col-CAT expression 1.5- to 9-fold. The CL receptor with thyroid hormone totally repressed TPA induction of the collagenase receptor. In the presence of thyroid hormone, the enhancing effects by S and G-H receptors on TPA-induced Col-CAT expression were unaffected and minimally diminished, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Ways
D K
DK
Department of Medicine, East Carolina University School of Medicine, Greenville, North Carolina 27858.
Qin
W
W
Cook
P
P
Parker
P J
PJ
Menke
J B
JB
Hao
E
E
Smith
A M
AM
Jones
C
C
Hershman
J M
JM
Geffner
M E
ME
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003062:Codon / Q000235:genetics; D017364:Collagenases / Q000096:biosynthesis / Q000235:genetics*; D015870:Gene Expression / Q000187:drug effects; D005799:Genes, Dominant; D006801:Humans; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D017354:Point Mutation; D011401:Promoter Regions, Genetic / Q000187:drug effects*; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D011988:Receptors, Thyroid Hormone / Q000235:genetics* / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014162:Transfection; D014284:Triiodothyronine / Q000494:pharmacology*
D003062:Codon; D009838:Oligodeoxyribonucleotides; D016755:Proto-Oncogene Proteins c-jun; D011988:Receptors, Thyroid Hormone; D014284:Triiodothyronine; D017364:Collagenases; D013755:Tetradecanoylphorbol Acetate