Characterization of the cAMP responsive elements from the genes for the alpha-subunit of glycoprotein hormones and phosphoenolpyruvate carboxykinase (GTP). Conserved features of nuclear protein binding between tissues and species.

Previous studies in our laboratory identified a negative regulatory domain in the 5'-flanking region of the human CYP1A1 gene containing two negative regulatory elements (NRE). Characterization of one of these elements revealed three nuclear protein binding regions: a 21-bp palindrome with a point of symmetry at -784 and two guanine- and cytosine-rich elements that flank the palindrome. Functional studies suggested the palindrome is critical for transcriptional repression, whereas the guanine- and cytosine-rich sequences play a secondary role. In this study, the interaction between nuclear proteins and the CYP1A1 NRE was further defined. Electrophoretic mobility shift assays (EMSA) indicated that the NRE -784 palindrome alone, but not the guanine- and cytosine-rich sequences minus the palindrome, was capable of specific nuclear protein binding. Competitive cotransfection experiments confirmed this observation in intact cells. Specific residues important for DNA-protein interactions were identified by site-directed mutagenesis and competitive EMSA. The loss of specific protein binding was also correlated with the loss of negative regulatory activity in a transient-expression assay. Finally, competitive EMSA was performed with consensus oligonucleotides for known transcription factors. An NF-Y consensus sequence efficiently competed with the NRE probe for specific nuclear protein binding. EMSA supershift analyses indicate that a protein immunologically related to NF-YB is part of the specific nuclear protein complex binding the human CYP1A1 NRE. These studies have refined our understanding of the sequences critical for the transcriptional repression of human CYP1A1. To our knowledge, this is also the first report implicating a member of the NF-Y transcription factor family in negative gene regulation.

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TATA-less Mouse Vitronectin Gene Promoter: Characterization of the Transcriptional Regulatory Elements and a Nuclear Protein Binding Site on the Promoter.

Cell Structure and Function ◽

10.1247/csf.23.23 ◽

1998 ◽

Vol 23 (1) ◽

pp. 23-32 ◽

Cited By ~ 5

Author(s):

Yasunori Miyamoto ◽

Kaori Hara ◽

Yoshiko Matsumoto ◽

Masao Hayashi

Keyword(s):

Protein Binding ◽

Binding Site ◽

Nuclear Protein ◽

Gene Promoter ◽

Regulatory Elements ◽

Protein Binding Site ◽

Transcriptional Regulatory Elements ◽

Promoter Characterization ◽

Transcriptional Regulatory

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Transient Prealbumin- Associated Hyperthyroxinemia in TSH-Producing Pituitary Adenoma

Nuklearmedizin ◽

10.1055/s-0038-1629511 ◽

1990 ◽

Vol 29 (01) ◽

pp. 40-43 ◽

Cited By ~ 3

Author(s):

W. Langsteger ◽

P. Költringer ◽

P. Wakonig ◽

B. Eber ◽

M. Mokry ◽

...

Keyword(s):

Computed Tomography ◽

Case Report ◽

Pituitary Adenoma ◽

Thyroid Hormones ◽

Protein Binding ◽

Alpha Subunit ◽

Normal Range ◽

Thyroxine Binding Globulin ◽

Free Thyroid Hormones ◽

Transmission Computed Tomography

This case report describes a 38-year-old male who was hospitalized for further clarification of clinically mild hyperthyroidism. His increased total hormone levels, the elevated free thyroid hormones and the elevated basal TSH with blunted response to TRH strongly suggested a pituitary adenoma with inappropriate TSH incretion. Transmission computed tomography showed an intrasellar expansion, 16 mm in diameter. The neoplastic TSH production was confirmed by an elevated alpha-subunit and a raised molar alpha-sub/ATSH ratio. However, T4 distribution on prealbumin (PA, TTR), albumin (A) and thyroxine binding globulin (TBG) showed a clearly increased binding to PA (39%), indicating additional prealbumin-associated hyperthyroxinemia. The absolute values of PA, A and TBG were within the normal range. After removal of the TSH-producing adenoma, basal TSH, the free thyroid hormones and T4 binding to prealbumin returned to normal. Therefore, the prealbumin-associated hyperthyroxinemia had to be interpreted as a transitory phenomenon related to secondary hyperthyroidism (T4 shift from thyroxine binding globulin to prealbumin) rather than a genetically conditioned anomaly of protein binding.

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