We identified cells of the developing superior cervical ganglia at post-fertilization in dwelling DbH transgenic fish and entirely mount in situ hybridization products with dbh and th riboprobes, indicating that EGFP expression within the developing embryonic PSNS of this transgenic line recapitulates the conventional endogenous expression patterns of dbh and th. By 80 hpf, EGFP was apparent within the superior cervical ganglia, along with in non PSNS dopaminergic nerves, like the medulla oblongata and cranial ganglia. By comparison, most MYCN transgenic embryos failed to express Vortioxetine a detectable level of EGFP fused to human MYCN in the superior cervical ganglia at 80 hpf, despite the fact that the fusion protein was demonstrably expressed in low PSNS tissues, and in most animals, the absence of detectable sympathoadrenal cells endured through 10 dpf. The lack of EGFP expression is consistent with the substantially reduced variety of sympathoadrenal cells in MYCN embryos indicated by the increasing loss of cells with endogenous th and dbh RNA expression by full mount in situ hybridization. Because th and dbh Organism are markers for classified sympathoadrenal cells, the absence of cells expressing EGFP MYCN under control of the dbh ally can reflect either MYCN induced apoptosis or an arrest in sympathoadrenal progenitor cell differentiation. To distinguish between these options, we first performed TUNEL and anti activated Caspase 3 staining on sections of 36, 51, and 72 hpf MYCN versus DbH transgenic fish. We found no proof of TUNEL or anti activated Caspase 3 good cells in the superior cervical ganglia or places where sympathoadrenal cells will be likely to form, indicating that the lack of detectable sympathoadrenal cells is not because of cell death, but instead to failing to begin the PSNS developmental program at this early time in development. To check this possibility, we performed total mount in situ hybridization at 80 hpf and 54 hpf for term of the phox2b, zash1a, and AP 2 CTEP leader genes, which encode transcription factors required for sympathoadrenal cell specification and maintenance. All of these sympathoadrenal cell progenitor indicators was easily detectable in the superior cervical ganglia region of control embryos, but invisible in MYCN transgenic embryos at these stages, suggesting that specification of the earliest recognizable sympathoadrenal cell progenitors was blocked by expression of the EGFP MYCN fusion gene. Since expression of the EGFP MYCN by non PSNS dopaminergic neuronal cells in these embryos was largely unaffected, including expression by cells of the medulla oblongata, locus coeruleus, and cranial ganglia, the suppression of sympathoadrenal cell development by EGFP MYCN is apparently tissue specific.