Table 1

Transcription factors involved in dopaminergic neurogenesis

Nurr 1
• Member of “zinc finger” superfamily of receptors; its subfamily includes nerve growth factor inducible B (NGFI-B) and neurone derived orphan receptor 1 (NOR-1)8
• Human gene on 2q22–23; eight exons, spanning 8 kb. Murine, rat, and human genes have similar structures9–12
• Full length mRNA has 3427 bases, 1794 are translated; the protein has 598 amino acids (66 kDa)16; splice variants exist—for example, Nurr 2—a novel cryptic exon located upstream in the Nurr 1 promoter region—and alternative splicing at exons 1, 2, and 613
• Potential regulatory region contains consensus binding sites for nuclear factor κB (NF-κB), cAMP response element binding protein (CREB), and Sp191114
• In the central nervous system (CNS) Nurr 1 expression occurs in the postmitotic late differential phase of dopaminergic precursor neuronal development,1516 detectable from rat embryonic day 10.517
• Nurr 1 response elements: a single half site (AAAGGTCA) binds Nurr 1 as monomer; this is the same sequence as the NGFI-B response element78; a direct repeat (DR5) (AGGTCANNNAAAGGTCA) binds Nurr 1/RXR as a heterodimer, Nurr 1 homodimers, and the Nurr 1/NGFI-B heterodimer18–20
• Nurr 1 response elements are found in tyrosine hydroxylase (AAAGGTCA),21 the dopamine transporter,22 and other molecules such as proopiomelanocortin23
• Structurally related to pentaxins—for example, C reactive protein and serum amyloid P; subfamily includes Ptx-1 and Ptx-2, and homeobox proteins such as Otx-1 and Otx-22425
• Human gene on chromosome 10.q25. has three exons26
• cDNA has 1861 bp; protein has 381 amino acids25; Ptx-3 is also a secreted, acute phase protein
• mRNA induced in endothelial, hepatic, and fibroblastic cells by interleukin 1β (IL-1β) and tumour necrosis factor α, but not by IL-6 and interferon γ; raised serum concentrations after bacterial lipopolysaccharide injection252728
• Expression is restricted in the CNS29
• The Ptx-3 response element is GGCTTT
• There is a Ptx-3 response element in the tyrosine hydroxylase gene30
• Mutations are associated with autosomal dominant cataracts26
• This transcription factor is related to members of the LIM family of homeobox proteins31
• The human gene is on 9q34 and has eight exons32
• Genetic mutations are associated with nail-patella syndrome33