Structural and functional characterization of the 5' upstream promoter of the human Phox2a gene: possible direct transactivation by transcription factor Phox2b.

摘要: The specification of neurotransmitter identity is a critical step in neural development. Recent progresses have indicated that the closely related homeodomain factors Phox2a and 2b are essential for development noradrenergic (NA) neuron differentiation, may directly determine identity. With long-term goal understanding regulatory cascade NA phenotype determination, we isolated characterized hPhox2a genomic clone encompassing approximately 7.5 kb 5' upstream promoter region, entire exon-intron structure, 4 3' flanking region. Using mRNAs from Phox2a-expressing human cell line, both primer extension 5'-rapid amplification cDNA ends analyses identified single transcription start site resides 172 nucleotides codon. was preceded by TATA-like sequence motif transcripts this contained an additional G residue at position, supporting authenticity as transcriptional hPhox2a. We assembled hPhox2a-luciferase reporter constructs containing different lengths sequences. Transient transfection assays these hPhox2a-positive -negative lines show 1.3-kb or longer sequences gene confer cell-specific expression. Furthermore, cotransfection Phox2a-negative HeLa line forced expression Phox2b, but not MASH1, significantly transactivates activity This study will provide frame to further delineate differentiation.