Previous Article | Next Article ![]()
Molecular and Cellular Biology, November 2005, p. 10171-10182, Vol. 25, No. 22
0270-7306/05/$08.00+0 doi:10.1128/MCB.25.22.10171-10182.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.
Cristina Luongo,2,
Antonia Elefante,2
Raffaele Ambrosio,2
Salvatore Salzano,3
Mariastella Zannini,1,3
Roberto Nitsch,1,3
Roberto Di Lauro,1
Guido Rossi,1
Gianfranco Fenzi,2 and
Domenico Salvatore2*
Dipartimento di Biologia e Patologia Cellulare e Molecolare,1 Dipartimento di Endocrinologia ed Oncologia Molecolare e Clinica, Università di Napoli "Federico II," 80131 Naples, Italy,2 Istituto di Endocrinologia ed Oncologia Sperimentale, CNR-IEOS, 80131 Naples, Italy3
Received 6 August 2005/ Accepted 28 August 2005
Thyroid transcription factor gene 1 (TTF-1) is a homeobox-containing gene involved in thyroid organogenesis. During early thyroid development, the homeobox gene Nkx-2.5 is expressed in thyroid precursor cells coincident with the appearance of TTF-1. The aim of this study was to investigate the molecular mechanisms underlying thyroid-specific gene expression. We show that the Nkx-2.5 C terminus interacts with the TTF-1 homeodomain and, moreover, that the expression of a dominant-negative Nkx-2.5 isoform (N188K) in thyroid cells reduces TTF-1-driven transcription by titrating TTF-1 away from its target DNA. This process reduced the expression of several thyroid-specific genes, including pendrin and thyroglobulin. Similarly, down-regulation of TTF-1 by RNA interference reduced the expression of both genes, whose promoters are sensitive to and directly associate with TTF-1 in the chromatin context. In conclusion, we demonstrate that pendrin and thyroglobulin are downstream targets in vivo of TTF-1, whose action is a prime factor in controlling thyroid differentiation in vivo.
Supplemental material for this article may be found at http://mcb.asm.org/.
M.D. and C.L. contributed equally to this work.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»