			Home About us Contact

Helix-loop-helix Transcription Factor (helix-loop-helix + transcription_factor)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Xenopus paraxis homologue shows novel domains of expression

DEVELOPMENTAL DYNAMICS, Issue 3 2004
Ronald Carpio
Abstract The paraxis gene encodes a basic helix-loop-helix transcription factor that is expressed in paraxial mesoderm and whose mutant displays an inability to form epithelial somites. Here, the molecular characterization of Xenopus paraxis is reported. paraxis is expressed in the paraxial mesoderm and somites but is down-regulated during muscle differentiation. In addition to its paraxial mesodermal expression, described in other organisms, two novel expression domains of paraxis were found: the neural tube and the head mesoderm. paraxis expression in the neural tube was compared with the expression of the neural markers Xash and Xiro1, and we concluded that paraxis is expressed in a broad band in the prospective sulcus limitans of the neural tube. Developmental Dynamics 231:609,613, 2004. © 2004 Wiley-Liss, Inc. [source]

Id1 expression is transcriptionally regulated in radial growth phase melanomas

INTERNATIONAL JOURNAL OF CANCER, Issue 8 2007
Byungwoo Ryu
Abstract Id genes have been demonstrated to be upregulated in a wide variety of human malignancies and their expression has been correlated with disease prognosis; however, little is known about the mechanisms of Id gene activation in tumors. We have previously shown that the helix-loop-helix transcription factor, Id1, is highly expressed in primary human melanomas during the radial growth phase and that Id1 is a transcriptional repressor of the familial melanoma gene CDKN2A. Here we use a series of melanoma cell lines that recapitulate the phenotypic characteristics of melanomas at varying stages of malignant progression to evaluate the expression levels of Id1 in this model system and determine the mechanism of Id1 dysregulation in these tumor cells. We find elevated protein levels of Id1 to be present consistently in radial growth phase tumor cells in accordance with our primary tumor data. Id1 transcript levels were also found to be elevated in these radial growth phase melanoma cells without any appreciable evidence of gene amplification and Id1 promoter activity was found to correlate with Id expression levels. We therefore conclude that Id1 expression is primarily regulated at the transcriptional level in radial growth phase melanomas and expect that therapies that target Id1 gene expression may be useful in the treatment of Id-associated malignancies. © 2007 Wiley-Liss, Inc. [source]

Bone morphogenetic protein 7 induces mesenchymal-to-epithelial transition in melanoma cells, leading to inhibition of metastasis

CANCER SCIENCE, Issue 11 2009
Yi-Rang Na
Bone morphogenetic protein (BMP) 7 counteracts physiological epithelial-to-mesenchymal transition, a process that is indicative of epithelial plasticity in developmental stages. Because epithelial-to-mesenchymal transition and its reversed process mesenchymal-to-epithelial transition (MET) are also involved in cancer progression, we investigated whether BMP7 plays a role in WM-266-4 melanoma cell growth and metastasis. An MTT assay was conducted in WM-266-4 and HEK293T cell lines to show the cell growth inhibition ability of BMP7 and cisplatin. Semiquantitative RT-PCR was used to determine MET in morphologically changed BMP7-treated melanoma cells. MET-induced cells expressed less a basic helix-loop-helix transcription factor (TWIST) in western blot analysis, and we confirm that BMP receptor (Alk2) siRNA transduction could restore TWIST protein expression via blocking of Smad 1, 5 and 8 signaling. Matrigel invasion and cell migration assays were done to investigate the BMP7-induced metastasis inhibition ability. BMP7 treatment only slightly reduced cell growth rate, but induced apparent MET. BMP7 also reduced the invasion and migration ability. Furthermore, BMP7 reduced the resistance of WM-266-4 cells to cisplatin. Collectively, our findings indicate that the metastatis inhibition ability of BMP7 is involved in MET, and that BMP7 could be used as a potential metastasis inhibitor in human melanoma cells. (Cancer Sci 2009) [source]

OLIG-1 and 2 gene expression and oligodendroglial tumours

NEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 2 2002
K. Hoang-Xuan
OLIG 1/2 genes encode basic helix-loop-helix transcription factors that play a critical role in motor neurone and oligodendrocyte fate specification during development. Two recent studies in which OLIG transcripts were detected by in situ hybridization have reported a high expression of the OLIG genes in oligodendrogliomas. This suggests that the detection of these lineage markers could become an adjunct to the classic morphological diagnosis of these tumours. There are problems in the diagnosis of oligodendroglioma. To date, all other known oligodendrocyte lineage markers have failed to label specifically neoplastic oligodendrocytes. Deletions on chromosome 1p and 19q are much more frequent in oligodendrogliomas than in astrocytomas but these molecular alterations are not constant. For the future, when routinely available, immunohistochemical techniques using anti-OLIG antibodies on paraffin embedded tissues will allow a systematic study of a large series of tumours so that we will know the specificity and sensitivity of this investigation in diagnosis. At another level, it is possible that expression of OLIG in neoplastic oligodendrocyte might participate in the oncogenesis of oligodendrogliomas. Initial work suggests that this is probably not the case. However further in vitro and in vivo studies analysing the functional consequence of OLIG overexpression in terms of proliferation and tumour progression are needed. [source]