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D Civitareale

Publications and source records attributed to D Civitareale.

4 recordsLinked to original sources
PubMed1990

The tissue-specific expression of the thyroglobulin gene requires interaction between thyroid-specific and ubiquitous factors.

Thyroid-specific expression of the rat thyroglobulin gene is mediated by transcriptional control. Sufficient DNA sequence information to confer thyroid-specific expression to a heterologous gene is contained between positions -168 and +39. DNA-binding studies have demonstrated that this region interacts with two thyroid-specific factors (TTF-1 and TTF-2), and a ubiquitous factor (UFA). Here we have characterized three elements within the promoter, A, K, and C, which are important for promoter activity in thyroid cells. We have shown by mutational analysis that the interaction of TTF-1 with the A and C regions. UFA with the A region, and TTF-2 with the K region are required for full promoter activity. The complex interactions in the A region can be replaced by the substitution of the UFA/TTF-1-binding site with a high-affinity TTF-1 binding site. There is a correlation between the presence of TTF-1 and TTF-2 DNA-binding activities and the expression of thyroglobulin, which implies that the mechanism restricting thyroglobulin expression to thyroid cells is mediated through the control of the expression, or the activity, of TTF-1 and TTF-2.

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PubMed1989

A thyroid-specific nuclear protein essential for tissue-specific expression of the thyroglobulin promoter.

A rat thyroglobulin promoter fragment, capable of directing thyroid-specific transcription, binds at least three different factors, TTF-1, TTF-2 and UFA, which are all present in nuclear extracts of the differentiated rat thyroid cell line FRTL-5. TTF-1 and TTF-2 are FRTL-5 specific, as demonstrated by their absence in nuclear extracts prepared from cell lines that do not express any thyroid-differentiated function, while UFA is present in all cell lines tested. TTF-1 has been extensively purified. It binds to the rat thyroglobulin promoter at three different sites which share sequence homology. Mutations in two of the three sites decrease both binding of TTF-1 in vitro and promoter function in vivo. This suggests that the tissue-specific expression of the thyroglobulin genes is mediated, at least in part, by the presence of a transcription factor exclusively in thyroid cells.

Animals↗
PubMed1987

Partial purification of a thyroid specific nuclear protein recognizing the thyroglobulin promoter.

We have used a gel retardation assay to follow the purification of a calf thyroid nuclear protein that binds to the -70 region of the rat thyroglobulin promoter. The activity producing the observed band shift is thyroid specific. The same shift is in fact observed with extracts prepared from a differentiated rat thyroid cell line which synthesizes and secretes thyroglobulin, while no similar shift is detected when cell unable to express their endogenous thyroglobulin gene or tissues different from thyroid are used as a source of nuclear extract. Competition experiments suggest that the same protein may bind at two different sites within the promoter. The two sites display considerable sequence homology. Sequence comparisons between the rat, calf and human promoter suggest that more than the sequence is the geometry of the promoter which is conserved.

Animals↗