Molecular cloning of a novel thyroid hormone-responsive gene, ZAKI-4, in human skin fibroblasts.
Utilizing a method called "differential display of mRNAs by means of polymerase chain reaction", the cDNA fragment of a thyroid hormone-responsive gene ZAKI-4 was cloned from cultured human skin fibroblasts. Northern blot analysis revealed that there were two ZAKI-4 mRNA species (3.4 and 1.4 kilobases (kb)), and they were up-regulated by a physiological concentration of triiodothyronine (T3). This T3 effect was abolished by the treatment with cycloheximide, indicating the possibility that gene ZAKI-4 is regulated by T3 in an indirect fashion, through an intermediate product of T3, rather directly by T3 itself. No effect of T3 on ZAKI-4 mRNA stability suggested that T3 induces the mRNA at the transcriptional level. Rapid amplification of cDNA ends confirmed the presence of two mRNA species. ZAKI-4 mRNA was detected in heart, brain, liver, and skeletal muscle but not in placenta, lung, kidney and pancreas. In skin fibroblasts and skeletal muscle, 3.4-kb mRNA was the major species, whereas 1.4-kb mRNA was dominant in heart, brain, and liver. The sequence analysis suggested that the two mRNA species arise from alternative polyadenylation and code a single protein of 192 amino acids. No homologous protein sequence was found in a data base. Elucidation of the function of ZAKI-4 gene product will provide new insights into an important role of T3 in various organs.
Miyazaki
T
T
Department of Endocrinology and Metabolism, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-01, Japan.
Kanou
Y
Y
Murata
Y
Y
Ohmori
S
S
Niwa
T
T
Maeda
K
K
Yamamura
H
H
Seo
H
H
D000293:Adolescent; D000328:Adult; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D001483:Base Sequence; D001921:Brain / Q000378:metabolism; D002478:Cells, Cultured; D002648:Child; D003001:Cloning, Molecular / Q000379:methods; D017931:DNA Primers; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D008099:Liver / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D009928:Organ Specificity; D016133:Polymerase Chain Reaction / Q000379:methods; D011247:Pregnancy; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D012867:Skin / Q000378:metabolism*; D014158:Transcription, Genetic; D014284:Triiodothyronine / Q000494:pharmacology*
D017931:DNA Primers; D009124:Muscle Proteins; D011506:Proteins; C100360:RCAN2 protein, human; D012333:RNA, Messenger; D014284:Triiodothyronine