Biomedical subjects

Naohiro Hori

Publications and source records attributed to Naohiro Hori.

4 recordsLinked to original sources

PubMed2006

Isolation, expression, and characterization of the human ZCRB1 gene mapped to 12q12.

While isolating morphine-dependence-related genes with differential display, we cloned a novel human gene, zinc finger CCHC-type and RNA-binding motif 1 (ZCRB1, alias MADP-1) encoding a nuclear protein (217 residues). The ZCRB1 gene consists of eight exons and seven introns. It is mapped to 12q12, which is within a locus reported for Parkinson disease (M. Funayama et al., Ann. Neurol. 51 (2002) 296-301). The 5'-flanking region contains an enhancer core motif and binding sites for AP-1, AP-2, and LF-A1. ZCRB1 is characterized by an RNA-binding motif and a CCHC zinc finger motif. The latter overlaps the C..C...GH....C core nucleocapsid motif. ZCRB1 is conserved from zebrafish to human and shares homology with cold-inducible RNA-binding protein. Transfection assay showed that ZCRB1 is located in the nucleoplasm, but outside the nucleolus. ZCRB1 gene expression was stimulated by morphine, inhibited by 30-36 degrees C, and up-regulated by 39 degrees C incubation in SH-SY5Y neural cells. Zcrb1 gene expression is highest in the heart and testes, lower in the cerebellum, and lowest in the liver in mice. ZCRB1 mRNA expression is specifically elevated in hepatocarcinoma HepG2 cells. These data provide new clues for further understanding of morphine dependence, heat shock, and hepatocarcinoma.

Amino Acid Sequence↗

PubMed2005

CCAAT/enhancer binding protein-beta (C/EBP-beta), a pivotal regulator of the TATA-less promoter in the rat catalase gene.

The rat catalase gene carries a TATA-less promoter and its transcriptional mechanism is interesting because of downregulation in liver injury. We characterized the core element in the promoter and found that C/EBP-beta binding downstream of the transcription initiation site plays a crucial role for transcription. The multiple complexes binding to the promoter were composed of homodimers and heterodimers of C/EBP-beta isoforms. Transduction of the C/EBP-beta gene showed complete reconstitution of multiple binding complexes in HeLa cells, similar to normal liver. Furthermore, C/EBP-beta was observed to bind to the endogenous catalase promoter. These data suggest that multiple complex formation of C/EBP-beta regulates transcription in the TATA-less catalase promoter.

Animals↗

PubMed2002

A dyad oct-binding sequence functions as a maintenance sequence for the unmethylated state within the H19/Igf2-imprinted control region.

DNA methylation of an imprinted control region (ICR) directs the allele-specific and reciprocal expression of the mouse H19 and the insulin-like growth factor 2 (Igf2) genes, mediated by controlling enhancer access. The ICR shows enhancer blocking activity through CTCF binding to an unmethylated sequence. The unmethylated state of the maternal ICR is maintained throughout development after establishment in the germ line; however, little is known of the molecular mechanisms that regulate DNA methylation. Hence, in this study we show that a dyad Oct-binding sequence (DOS) in the ICR mediates the demethylation of low-density methylation but not hypermethylation and is required to maintain the unmethylated state against the tendency for de novo methylation within the ICR in the embryonic carcinoma cell line P19. Furthermore, we also reveal that the unmethylated state of at least one CTCF-binding site within the ICR is under the control of DOS. Our results suggest that the ICR, as a CTCF-dependent insulator, requires DOS as well as CTCF-binding sites and that DOS maintains the maternal specific unmethylated state of the ICR at postimplantation stages.

Animals↗

PubMed2002

Identification of differentially expressed genes in rat hepatoma cell lines using subtraction and microarray.

Rat hepatoma Fao is a well-differentiated cell line that expresses numerous liver-specific enzymes and liver-enriched transcription factors, whereas the C2 cell line derived from Fao exhibits dedifferentiated phenotypes and fails to express these differentiated traits. Hence, to identify the gene related to the differentiation status in these cells, we analyzed differentially expressed genes between Fao and C2 cells using a microarray of 1,000 identified cDNA clones, and isolated a cDNA clone from subtractive library constructed by suppression subtractive hybridization. D6.1A, a member of the tetraspanin protein superfamily, was identified as a gene enhanced in C2 cells compared with Fao cells. Interestingly, expression of this gene was also induced following liver injury by CCl(4) and in liver regeneration following partial hepatectomy. These results suggest that the D6.1A gene is related to stimulation of cell proliferation and differentiation status in C2 hepatoma cells.

Animals↗