The galectin-3 gene promoter binding proteins in the liver of rats 48-h post-treatment with CCl4.
The present study was undertaken to characterize structure-function relationships of the rat galectin-3 gene promoter especially focusing on the promoter binding proteins included in livers injured with CCl4. Transcription start site determination identified a 66-nucleotide-long exon 1 of this gene. Transient expression analysis using a reporter luciferase gene assigned a region between -161 and -15 to the proximal promoter within the 1-kb region flanking the 5'-end of exon 1. The rat galectin-3 gene promoter possesses a Runx2 binding site and inverted repeats of Sp1 binding motifs in separate regions downstream from -117 as structures resembling those of the mouse galectin-3 gene promoter. The -161/-118 region bound two different proteins. One is a novel protein, a rat version of Purbeta that binds to a guanine nucleotide pair at -145 and -144 to modulate constitutive galectin-3 gene transcription. Southwestern blot analysis using the -161/-118 ligand revealed a signal of a 50-kDa protein in liver nuclear extracts from rats 48-h post-treatment with CCl4, but not in those from Ac2F cells and normal rat livers. The inducible nature of this protein suggested its distinctive role in galectin-3 induction in a liver injured with CCl4. E-box and peroxisome proliferator response element-like motifs reside on separate DNA strands from -140 to -135. Contribution of this segment to the regulation of galectin-3 gene transcription under pathological conditions was suggested, since a DNA ligand with the two motifs simultaneously mutagenized at -136 and -137 was not bound by the 50-kDa protein.
Li
Fang
F
The Department of Biochemistry, Toyama Medical and Pharmaceutical University School of Medicine, 2630 Sugitani, Toyama 930-0194, Japan.
Kato
Ichiro
I
Kawaguchi
Hiroshi
H
Takasawa
Kumi
K
Hibino
Yasuhide
Y
Hiraga
Koichi
K
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002251:Carbon Tetrachloride / Q000633:toxicity*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology; D002352:Carrier Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D005091:Exons; D037502:Galectin 3 / Q000737:chemistry / Q000235:genetics*; D017930:Genes, Reporter; D008099:Liver / Q000293:injuries*; D008113:Liver Neoplasms / Q000378:metabolism / Q000473:pathology; D008156:Luciferases / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D051381:Rats; D017208:Rats, Wistar; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D013997:Time Factors; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D024363:Transcription Initiation Site; D014158:Transcription, Genetic
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D037502:Galectin 3; C508560:PurB protein, rat; D014157:Transcription Factors; D002251:Carbon Tetrachloride; D008156:Luciferases