Open AccessAn In Vitro Approach to Test the Possible Role of Candidate Factors in the Transcriptional Regulation of the <I>RET</I> Proto-Oncogene
Author(s) -
Tiziana Bachetti,
Silvia Borghini,
Roberto Ravazzolo,
Isabella Ceccherini
Publication year - 2005
Publication title -
gene expression
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 46
eISSN - 1555-3884
pISSN - 1052-2166
DOI - 10.3727/000000005783992106
Subject(s) - neural crest , luciferase , biology , transfection , transcription factor , reporter gene , cell culture , gene , oncogene , microbiology and biotechnology , in vitro , promoter , transcriptional regulation , transcription (linguistics) , genetics , gene expression , cell cycle , linguistics , philosophy
Neural crest cells arise from the epithelium of the dorsal neural tube and migrate to various districts giving origin, among others, to sympathetic, parasympathetic, and enteric ganglia. It has been shown that the transcription factors HOX11L1, HOX11L2, MASH1, PHOX2A, and PHOX2B are all necessary, to various extents, to the correct development of the autonomic nervous system. To investigate their possible role in the transcriptional regulation of the RET proto-oncogene, a gene playing a crucial role in correct intestinal innervation, we undertook a specific in vitro experimental strategy. Two neuroblastoma cell lines (SK-N-MC and SK-N-BE) were cotransfected with each transcription factor expressing plasmids and sequential deletion constructs of the 5' c-RET flanking region cloned upstream of the Luciferase reporter gene. Here we show that HOX11L1 enhances the activity of the c-RET promoter in SK-N-MC cell line by stimulating a region between -166 bp and -35 bp. Gel shift assays performed with oligonucleotides spanning this promoter sequence showed a change of the SP1 interaction with its binding sites, consequent to transfection with HOX11L1. While HOX11L2 showed no effect in both the cell lines, we have observed PHOX2A, PHOX2B, and MASH1 triggering a reproducible increase in the Luciferase activity in SK-N-BE cell line. A sequence responsible of the PHOX2A-dependent activation has been identified, while PHOX2B seems to act indirectly, as no physical binding has been demonstrated on c-RET promoter.