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K Morohashi

Publications and source records attributed to K Morohashi.

At least 19 recordsLinked to original sources
PubMed2005

A steroidogenic cell line with differentiation potential from mouse granulosa cells, transfected with Ad4BP and SV40 large T antigen genes.

Several steroidogenic cell lines of granulosa cells (GC) have been used to elucidate differentiation mechanisms of GC during folliculogenesis. These cell lines, however, are of limited usefulness since they have lost some of their differentiation potential. The transcription factor adrenal-4 binding protein (Ad4BP), also known as steroidogenic factor-1 or NR5A1, is essential for the expression of all P-450 steroidogenic enzymes. By transfection with the Ad4BP gene together with SV40 DNA, we have generated several steroidogenic cell lines. One selective clone, named 4B2, retained its steroidogenic potential and was therefore analyzed in depth. This cell line responded to 8-Br-cAMP by displaying differentiation characteristics similar to those occurring in the differentiation process of primary cultured GC, including enhanced progesterone secretion, a cell shape change from a fibroblastic to epithelioid conformation, elongated mitochondria, increased gap junction formation and inhibition of cell proliferation. Prostaglandin E2 (PGE2), an intraovarian regulator of GC, stimulated cAMP production, and this eicosanoid, like 8-Br-cAMP, induced differentiation properties with the exception of cell conformation in 4B2 cells. These results suggest that expression of Ad4BP may provide the basis for a repertoire of cAMP-sensitive differentiation properties, including morphological alterations and growth inhibition. Thus, the 4B2 cell line may serve as a tool for elucidation of differentiation mechanisms that are under the control of Ad4BP.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed2002

Association of single nucleotide polymorphisms in the IL-18 gene with sarcoidosis in a Japanese population.

Interleukin-18 (IL-18) and interleukin-12 (IL-12) synergistically stimulate interferon-gamma (IFN-gamma) production from Th1 cells. The levels of serum IL-18 and IFN-gamma and bronchoalveolar lavage fluid IL-18 were elevated in patients with sarcoidosis. The polymorphisms of the IL-18 gene may play a possible role in expression regulation of the gene. We investigated the roles of the polymorphisms in the development of sarcoidosis. We examined two single nucleotide polymorphisms of the IL-18 gene in 119 patients with sarcoidosis and 130 healthy control subjects. Our results showed that the frequency of sarcoidosis patients with the CA genotype at position -607 was significantly higher than that with the AA genotype (OR = 2.200) and a significantly higher proportion of patients had the C allele at -607 compared with that of the controls (OR = 2.123). No significant differences were seen in the distribution of the genotypes or phenotype frequencies at position -137. There was no specific organ involvement associated with a certain genotype or phenotype. In IL-18 gene polymorphisms, the C allele at position -607 might be a genetic risk factor for sarcoidosis in this Japanese population.

Adult↗
PubMed2000

Identification of novel first exons in Ad4BP/SF-1 (NR5A1) gene and their tissue- and species-specific usage.

It has been demonstrated that the mammalian Ad4BP/SF-1 (NR5A1) gene is regulated precisely in sex, tissue, and developmental stage specific manners. To clarify the complex transcriptional regulation, we investigated in the present study whether the gene transcription is regulated by multiple promoters accompanied by noncoding first exons. Novel first exons (Io and Ig) were identified downstream of the already identified exon Ia. Nucleotide sequences revealed that Ia and Ig exons were well conserved, whereas Io exon was less conserved among the mouse, rat, and human genes. Interestingly, the splice donor of the mouse and human Io and human Ig exons do not satisfy the consensus sequence. Transcripts containing Ia, Io, and Ig were detected in all rat tissues examined, while the transcript containing Io was undetectable in the corresponding tissues of mice. The lack of exon Io usage in the mouse was confirmed by transient transfection assays with cultured cells. Quantitative RT-PCR analysis revealed that the transcript containing Ig exon was the main product in the pituitary but significantly less in the spleen, suggesting that the regulation of Ad4BP/SF-1 gene transcription in the pituitary and spleen is distinct from that of other tissues. The above findings, together with the structural abnormality at the splice donor site, suggest that acquisition of the multiple first exons enables the Ad4BP/SF-1 gene to be regulated differentially in different animal species and in different tissues in the same animal.

Alternative Splicing↗
PubMed2000

Orphan receptors COUP-TF and DAX-1 as targets in disordered CYP17 expression in adrenocortical tumors.

CYP17 gene transcription is activated by SF-1 binding to a cyclic AMP-responsive sequence within the promoter region of the gene, and its transcription is inhibited by COUP-TF binding to the sequence. Another orphan receptor, DAX-1, is shown to act as a suppressor of SF-1-mediated transcription. We examined the expression level of these orphan receptors in adrenocortical tumors and compared the results with CYP17 expression. CYP17 was highly expressed in cortisol-producing adenomas, whereas COUP-TF and DAX-1 expression levels were very low. In deoxycorticosterone-producing adenomas, on the other hand, CYP17 expression was extremely low, whereas DAX-1 was highly expressed and SF-1 expression was slightly decreased. In conclusion, the reciprocal expression of CYP17 and the transcriptional repressors COUP-TF and DAX-1 indicates that these orphan receptors have a pathophysiologic role in the excessive hormone production in cortisol- and deoxycorticosterone-producing adrenocortical tumors.

Adrenal Cortex Neoplasms↗
PubMed1999

Sex reversal caused by Mus musculus domesticus Y chromosomes linked to variant expression of the testis-determining gene Sry.

When the Y chromosomes from certain populations of Mus musculus domesticus are introduced into the mouse strain C57BL/6 (B6), testis determination can fail, resulting in gonads developing either as ovotestes (with both ovarian and testicular components) or as ovaries. Not all Y(DOM) chromosomes cause sex reversal. Y(DOM) chromosomes are divided into three classes based upon their ability to induce testes in B6. The molecular basis underlying the three Y(DOM) classes is an enigma. The simplest explanation is that they harbor different alleles of the testis-determining gene, Sry. Sequencing of Sry(DOM) genes has indeed identified polymorphisms. However, none were unequivocally linked to the sex-reversal trait. It was concluded that all SRY(DOM) proteins are functionally equivalent. Using a semiquantitative RT-PCR assay, we now show that representatives of the three Y(DOM) classes have variant Sry expression patterns, that severity of sex reversal correlates with Sry mRNA titers, and that genetic correction of the sex reversal results in the upregulation of Sry expression. We propose that the variant Sry expression patterns result from polymorphisms at the site of a putative Sry enhancer.

3' Untranslated Regions↗
PubMed1999

Structural and functional abnormalities in the spleen of an mFtz-F1 gene-disrupted mouse.

The spleen has two main functions. The first is to provide a proper microenvironment to lymphoid and myeloid cells, whereas the second involves clearance of abnormal erythrocytes. Ad4BP/SF-1, a product of the mammalian FTZ-F1 gene (mFTZ-F1), was originally identified as a steroidogenic, tissue-specific transcription factor. Immunohistochemical examination of the mammalian spleens confirmed the expression of Ad4BP/SF-1 in endothelial cells of the splenic venous sinuses and pulp vein. In mFtz-F1 gene-disrupted (KO) mice, several structural abnormalities were detected in the spleen, including underdevelopment and nonuniform distribution of erythrocytes. Examination of the spleen of KO fetuses showed failure of development of certain tubular structures during embryogenesis. These structures are normally assembled by Ad4BP/SF-1 immunoreactive cells, and most likely form the vascular system during later stages of development. Other structural abnormalities in the spleen of the KO mice included defects in the tissue distribution of type-IV collagen, laminin, c-kit, and vimentin. These morphologic defects in the vascular system were associated with a decrease in the proportion of hematopoietic cells, although differentiation of these cells was not affected significantly. A high number of abnormal red blood cells containing Howell-Jolly bodies were noted in the KO mice, indicating impaired clearance by the splenic vascular system. We also detected the presence of an mRNA-encoding cholesterol side-chain cleavage P450 in the spleen, resembling the findings in steroidogenic tissues such as the gonads and adrenal cortex. The mRNA transcript was not involved in splenic structural defects as it was detected in the spleens of both normal and KO mice, indicating that the regulatory mechanism of the P450 gene in the spleen is different from that in steroidogenic tissues. Our results indicate that a lack of the mFtz-F1 gene in mice is associated with structural and functional abnormalities of the splenic vascular system.

Animals↗
PubMed1999

Dax-1 as one of the target genes of Ad4BP/SF-1.

The DAX-1 (also known as AHC) gene encodes an unusual member of the nuclear hormone receptor superfamily. DAX-1 plays a critical role during gonadal and adrenal differentiation since mutations of the human DAX-1 gene cause X-linked adrenal hypoplasia congenita associated with hypogonadotropic hypogonadism. In recent studies, DAX-1 was reported to function as a transcriptional suppressor of Ad4BP/SF-1, a critical transcription factor in gonadal and adrenal differentiation. With respect to implication of Ad4BP/SF-1 in the transcriptional regulation of the DAX-1 gene, inconsistent findings have been previously reported. We investigated the upstream region of the mouse Dax-1 (also known as Ahch) gene and identified a novel Ad4/SF-1 site by transient transfection and electrophoretic mobility shift assays. In addition, immunohistochemical analyses with a specific antibody to Dax-1 indicated the presence of immunoreactive cells in steroidogenic tissues, pituitary gland, and hypothalamus. Although the distributions of Dax-1 and Ad4BP/SF-1 were very similar, they were not completely identical. The expression of Dax-1 was significantly impaired in knock-out mice of the Ftz-f1 gene, which encodes Ad4BP/ SF-1. Taken together, our findings indicate that Ad4BP/SF-1 controls the transcription of the Dax-1 gene.

Adrenal Cortex Neoplasms↗
PubMed1998

Molecular cloning and expression of the SF-1/Ad4BP gene in the frog, Rana rugosa.

SF-1/Ad4BP is a transcriptional factor that was originally found to be a mammalian homologue of the Drosophila Ftz-F1 (fushi tarazu factor 1) (), and transcribed from a gene designated the Ftz-F1 gene (). Ftz-F1 gene-deficient mice lack adrenal glands and gonads. Besides mammals, however, the SF-1/Ad4BP cDNA has only been isolated to date in fish and birds. To understand its role(s) for adrenal and gonadal development in vertebrates, cloning of this gene in animals other than mammals is required. In this study, we succeeded to isolate frog (Rana rugosa) SF-1/Ad4BP cDNA from a testis lambdagt10 cDNA library. It encoded a protein of 468 amino acids, and its open reading frame (ORF) shared 70% similarity with that of chicken OR2.1 (a SF-1/Ad4BP homologue) and 62% with bovine SF-1/Ad4BP. SF-1/Ad4BP mRNA was expressed in the testes, brains, adrenals/kidneys and spleens, but not ovaries, of adult frogs. In addition, we also cloned the 5'-untranslated region (4.6kb) of the SF-1/Ad4BP gene with exons I and II. Genomic structure analysis revealed that frog SF-1/Ad4BP was also transcribed from the same gene as that of mammals. However, many Ftz-F1-related proteins have been reported so far. The Ftz-F1 gene does not encode all of those Ftz-F1-related proteins. Thus, the name of Ftz-F1 is not adequate for the gene coding SF-1/Ad4BP. Here, we propose the use of SF-1/Ad4BP instead of Ftz-F1 for the gene that encodes SF-1/Ad4BP in vertebrates.

5' Untranslated Regions↗
PubMed1998

Adrenocortical and gonadal expression of the mammalian Ftz-F1 gene encoding Ad4BP/SF-1 is independent of pituitary control.

Ad4BP/SF-1 is a transcription factor essential for the development of the adrenal gland and the gonads as well as for the maintenance of their functions through regulating tissue-specific gene transcription. In the whole body, hypothalamo-pituitary-gonadal and -adrenal axes are known to play prominent roles in mediating the function of the gonads and adrenal. In this study, the effects of the tropic peptide hormones secreted by the pituitary on the regulation of the rat Ftz-F1 (rFtz-F1) gene encoding Ad4BP/SF-1 were investigated. Immunochemical studies revealed that Ad4BP/SF-1 was expressed even in the adrenal cortex of hypophysectomized rats. Such persistent expression of Ad4BP/SF-1 was also observed in the testes and ovaries of the hypophysectomized animals. In contrast to Ad4BP/SF-1, the expressions of steroidogenic P450s were reduced significantly. The transcriptional activities of the endogenous and transfected rFtz-F1 genes were examined with Y-1 and I-10 cells derived from mouse adrenocortical and testicular Leydig cell tumors, respectively. Neither gene appeared to be activated significantly by cAMP, whereas both endogenous and exogenous CYP11A genes encoding P450(SCC) were activated. Taken together, these observations indicate that the expression of the rFtz-F1 gene is mainly regulated by a mechanism independent of the neuroendocrine axes.

Adrenal Cortex↗
PubMed1998

[Function and expression of transcription factors implicated in gonadal differentiation].

Several transcription factors such as SRY, DAX-1, Ad4BP/SF-1, WT-1 and SOX -9, have been revealed to be implicated in gonadal development by analyzing the genetic disorders of human and the gene disrupted mice. All of these transcription factors are expressed in the early stage of the gonadal development and the expression profiles during the gonadal development are clearly different between the two sexes. Functions of the transcription factors are discussed by referring genes under the control of these factors. Effects of endocrine disruptants on the expression of Ad4BP/SF-1 in the fetal gonads was also discussed.

Animals↗
PubMed1997

Synergistic activation of the human type II 3beta-hydroxysteroid dehydrogenase/delta5-delta4 isomerase promoter by the transcription factor steroidogenic factor-1/adrenal 4-binding protein and phorbol ester.

Steroidogenic factor-1/adrenal 4-binding protein (SF-1/Ad4BP) is an orphan nuclear receptor/transcription factor known to regulate the P450 steroid hydroxylases; however, mechanisms that regulate the activity of SF-1/Ad4BP are not well defined. In addition, little is known about the mechanisms that regulate the human steroidogenic enzyme, type II 3beta-hydroxysteroid dehydrogenase (3beta-HSD II), the major gonadal and adrenal isoform. Regulation of the 3beta-HSD II promoter was examined using human adrenal cortical (H295R; steroidogenic) and cervical (HeLa; non-steroidogenic) carcinoma cells. H295R cells were transfected with a series of 5' deletions of 1251 base pairs (bp) of the 3beta-HSD II 5'-flanking region fused to a chloramphenicol acetyltransferase (CAT) reporter gene followed by treatment with or without phorbol ester (phorbol 12-myristate 13-acetate; PMA). CAT assay data indicated that the region from -101 to -52 bp of the promoter was required for PMA-induced expression. A putative SF-1/Ad4BP regulatory element, TCAAGGTAA, was identified by sequence homology at -64 to -56 bp of the promoter. Cotransfection of HeLa cells with the -101 3beta-HSD-CAT construct and an expression vector for SF-1/Ad4BP increased CAT activity 49-fold. Subsequent treatment with PMA induced an unexpected synergistic increase in transcriptional activity 540-fold over basal. Mutation of the putative response element (TCAAGGTAA to TCAATTTAA) abolished SF-1-induced CAT activity and the synergistic response to PMA. Gel mobility shift assays confirmed that SF-1/Ad4BP interacts with the putative element and transcripts for SF-1/Ad4BP were detected in H295R cells by Northern analysis. These data are the first to demonstrate 1) regulation of a non-cytochrome P450 steroidogenic enzyme promoter by SF-1/Ad4BP, 2) a powerful synergistic effect of PMA on SF-1/Ad4BP-induced transcription, and 3) the importance of the SF-1/Ad4BP regulatory element in the regulation of the 3beta-HSD II promoter.

Adrenal Cortex↗