Transcriptional regulation of RET by Nkx2-1, Phox2b, Sox10, and Pax3.
BACKGROUND
The rearranged during transfection (RET) gene encodes a single-pass receptor whose proper expression and function are essential for the development of enteric nervous system. Mutations in RET regulatory regions are also associated with Hirschsprung disease (HSCR) (aganglionosis of the colon). We previously showed that 2 polymorphisms in RET promoter are associated with the increased risk of HSCR. These single nucleotide polymorphisms overlap with the NK2 homeobox 1 (Nkx2-1) binding motif interrupting the physical interaction of NKX2-1 with the RET promoter and result in reduced RET transcription. In this study, we further delineated Nkx2-1-mediated RET Transcription.


RESULTS
First, we demonstrated that PHOX2B, like SOX10 and NKX2-1, is expressed in the mature enteric ganglions of human gut by immunohistochemistry. Second, subsequent dual-luciferase-reporter studies indicated that Nkx2-1 indeed works coordinately with Phox2b and Sox10, but not Pax3, to mediate RET transcription. In addition, identification of Phox2b responsive region in RET promoter further provides solid evidence of the potential functional interaction between Phox2b and RET.


CONCLUSIONS
In sum, Phox2b and Sox10 act together with Nkx2.1 to modify RET signaling and this interaction may also contribute to HSCR susceptibility.
Division of Paediatric Surgery, Department of Surgery, The University of Hong Kong, Hong Kong SAR, China.
Thomas Y Y
TY
Leon
Elly S W
ES
Ngan
Hiu-Ching
HC
Poon
Man-Ting
MT
So
Vincent C H
VC
Lui
Paul K H
PK
Tam
Maria Mercedes
MM
Garcia-Barcelo
D000818:Animals; D045744:Cell Line, Tumor / Q000378:metabolism; D017615:Enteric Nervous System / Q000378:metabolism; D004843:Epistasis, Genetic / Q000235:genetics; D005786:Gene Expression Regulation / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D006627:Hirschsprung Disease / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D051379:Mice; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors / Q000235:genetics / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D051096:Proto-Oncogene Proteins c-ret / Q000235:genetics* / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D055757:SOXE Transcription Factors / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics; D014162:Transfection / Q000706:statistics & numerical data
D018398:Homeodomain Proteins; C109220:NBPhox protein; C000614414:Nkx2-1 protein, mouse; D009687:Nuclear Proteins; D000072041:PAX3 Transcription Factor; C489409:PAX3 protein, human; D051761:Paired Box Transcription Factors; C527923:SOX10 protein, human; D055757:SOXE Transcription Factors; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases