Cory Huang | Columbia University (original) (raw)

Papers by Cory Huang

Research paper thumbnail of Transcription of the human ferredoxin gene through a single promoter which contains the 3',5'-cyclic adenosine monophosphate-responsive sequence and Sp 1-binding site

Molecular Endocrinology, Sep 1, 1992

Both bovine and human ferredoxin genes consist of four exons and three introns (3,4). The human g... more Both bovine and human ferredoxin genes consist of four exons and three introns (3,4). The human genome contains, in addition to the expressed ferredoxin gene, two pseudogenes that are located on separate chromosomes (5, 6). The intronless nature of the pseudogene suggests that it may have arisen by retroposonmediated events (6). One Alu sequence is located about 1 kilobase (kb) upstream from the active gene, and two more are found flanking the pseudogene $FDX3 (7, 8). Other than these differences, the human and bovine genes are very similar. Both have multiple functional polyadenylation signals giving mRNAs of different lengths in the 3'-region (4, 9).

Research paper thumbnail of Regulation of ferredoxin gene in steroidogenic and nonsteroidogenic cells

The Journal of Steroid Biochemistry and Molecular Biology, 1995

Ferredoxin is an electron transport intermediate for all the mitochondrial cytochromes P450. It i... more Ferredoxin is an electron transport intermediate for all the mitochondrial cytochromes P450. It is especially abundant in steroidogenic organs where it functions in steroid biosynthesis. The regulation of ferredoxin gene expression was studied in both steroidogenic and nonsteroidogenic cell lines. In steroidogenic cell line Y1, the expression of ferredoxin was stimulated by cAMP and repressed slightly by angiotensin II and phorbol ester PMA. These drugs exhibited the same effect on the basal promoter of the ferredoxin gene, which includes one TATA box and an SP1 site. In human adrenocortical cell line H295, the stimulation of the ferredoxin gene by cAMP was blocked by cycloheximide, as observed in bovine adrenocortical cell culture. In nonsteroidogenic cell lines such as HeLa and COS-1, the stimulation of ferredoxin gene expression by cAMP was not observed, although basal expression was strong. Transfection studies showed that the ferredoxin promoter could not be stimulated by cAMP in nonsteroidogenic cells. Therefore the steroidogenic cell-specific regulation and the general expression pattern appears to be a property unique to the ferredoxin gene.

Research paper thumbnail of Differential Regulation of the CYP11A1 (P450scc) and Ferredoxin Genes in Adrenal and Placental Cells

DNA and Cell Biology, 1993

The regulation of the genes encoding cholesterol side-chain cleavage enzyme (P450scc) and ferredo... more The regulation of the genes encoding cholesterol side-chain cleavage enzyme (P450scc) and ferredoxin, two components in the first step of steroid synthetic pathways, was studied by RNA analyses of endogenous and transfected genes. cAMP rather than calcium was the major secondary messenger that stimulated expression of both P450scc and ferredoxin genes in human placental JEG-3 cells. The effect of cAMP on P450scc expression was abolished by cycloheximide in JEG-3 cells, but it was superinduced in mouse adrenal Yl cells. For ferredoxin expression, both reagents have synergistic effect in Yl and JEG-3 cells. To test the mechanism of regulation, DNA segments containing regulatory elements of the P450scc and ferredoxin genes were connected to reporter genes and analyzed in cotransfection experiments. The results showed that the proximal cAMP-responsive sequences of both P450scc and ferredoxin genes were stimulated by cAMP early in both Yl and JEG-3 cells, requiring no new protein synthesis. This indicates a common mechanism for the regulated expression of both genes. P450scc possessed an additional upstream cAMP-responsive sequence that also responded to cAMP induction in a different manner from the proximal element. The presence of additional upstream regulatory elements makes it possible for the P450scc gene to be further regulated.

Research paper thumbnail of Transcription of the human ferredoxin gene through a single promoter which contains the 3',5'-cyclic adenosine monophosphate-responsive sequence and Sp 1-binding site

Molecular Endocrinology, 1992

Both bovine and human ferredoxin genes consist of four exons and three introns (3,4). The human g... more Both bovine and human ferredoxin genes consist of four exons and three introns (3,4). The human genome contains, in addition to the expressed ferredoxin gene, two pseudogenes that are located on separate chromosomes (5, 6). The intronless nature of the pseudogene suggests that it may have arisen by retroposonmediated events (6). One Alu sequence is located about 1 kilobase (kb) upstream from the active gene, and two more are found flanking the pseudogene $FDX3 (7, 8). Other than these differences, the human and bovine genes are very similar. Both have multiple functional polyadenylation signals giving mRNAs of different lengths in the 3'-region (4, 9).

Research paper thumbnail of Transcription of the human ferredoxin gene through a single promoter which contains the 3',5'-cyclic adenosine monophosphate-responsive sequence and Sp 1-binding site

Molecular Endocrinology, Sep 1, 1992

Both bovine and human ferredoxin genes consist of four exons and three introns (3,4). The human g... more Both bovine and human ferredoxin genes consist of four exons and three introns (3,4). The human genome contains, in addition to the expressed ferredoxin gene, two pseudogenes that are located on separate chromosomes (5, 6). The intronless nature of the pseudogene suggests that it may have arisen by retroposonmediated events (6). One Alu sequence is located about 1 kilobase (kb) upstream from the active gene, and two more are found flanking the pseudogene $FDX3 (7, 8). Other than these differences, the human and bovine genes are very similar. Both have multiple functional polyadenylation signals giving mRNAs of different lengths in the 3'-region (4, 9).

Research paper thumbnail of Regulation of ferredoxin gene in steroidogenic and nonsteroidogenic cells

The Journal of Steroid Biochemistry and Molecular Biology, 1995

Ferredoxin is an electron transport intermediate for all the mitochondrial cytochromes P450. It i... more Ferredoxin is an electron transport intermediate for all the mitochondrial cytochromes P450. It is especially abundant in steroidogenic organs where it functions in steroid biosynthesis. The regulation of ferredoxin gene expression was studied in both steroidogenic and nonsteroidogenic cell lines. In steroidogenic cell line Y1, the expression of ferredoxin was stimulated by cAMP and repressed slightly by angiotensin II and phorbol ester PMA. These drugs exhibited the same effect on the basal promoter of the ferredoxin gene, which includes one TATA box and an SP1 site. In human adrenocortical cell line H295, the stimulation of the ferredoxin gene by cAMP was blocked by cycloheximide, as observed in bovine adrenocortical cell culture. In nonsteroidogenic cell lines such as HeLa and COS-1, the stimulation of ferredoxin gene expression by cAMP was not observed, although basal expression was strong. Transfection studies showed that the ferredoxin promoter could not be stimulated by cAMP in nonsteroidogenic cells. Therefore the steroidogenic cell-specific regulation and the general expression pattern appears to be a property unique to the ferredoxin gene.

Research paper thumbnail of Differential Regulation of the CYP11A1 (P450scc) and Ferredoxin Genes in Adrenal and Placental Cells

DNA and Cell Biology, 1993

The regulation of the genes encoding cholesterol side-chain cleavage enzyme (P450scc) and ferredo... more The regulation of the genes encoding cholesterol side-chain cleavage enzyme (P450scc) and ferredoxin, two components in the first step of steroid synthetic pathways, was studied by RNA analyses of endogenous and transfected genes. cAMP rather than calcium was the major secondary messenger that stimulated expression of both P450scc and ferredoxin genes in human placental JEG-3 cells. The effect of cAMP on P450scc expression was abolished by cycloheximide in JEG-3 cells, but it was superinduced in mouse adrenal Yl cells. For ferredoxin expression, both reagents have synergistic effect in Yl and JEG-3 cells. To test the mechanism of regulation, DNA segments containing regulatory elements of the P450scc and ferredoxin genes were connected to reporter genes and analyzed in cotransfection experiments. The results showed that the proximal cAMP-responsive sequences of both P450scc and ferredoxin genes were stimulated by cAMP early in both Yl and JEG-3 cells, requiring no new protein synthesis. This indicates a common mechanism for the regulated expression of both genes. P450scc possessed an additional upstream cAMP-responsive sequence that also responded to cAMP induction in a different manner from the proximal element. The presence of additional upstream regulatory elements makes it possible for the P450scc gene to be further regulated.

Research paper thumbnail of Transcription of the human ferredoxin gene through a single promoter which contains the 3',5'-cyclic adenosine monophosphate-responsive sequence and Sp 1-binding site

Molecular Endocrinology, 1992

Both bovine and human ferredoxin genes consist of four exons and three introns (3,4). The human g... more Both bovine and human ferredoxin genes consist of four exons and three introns (3,4). The human genome contains, in addition to the expressed ferredoxin gene, two pseudogenes that are located on separate chromosomes (5, 6). The intronless nature of the pseudogene suggests that it may have arisen by retroposonmediated events (6). One Alu sequence is located about 1 kilobase (kb) upstream from the active gene, and two more are found flanking the pseudogene $FDX3 (7, 8). Other than these differences, the human and bovine genes are very similar. Both have multiple functional polyadenylation signals giving mRNAs of different lengths in the 3'-region (4, 9).