Key basic helix-loop-helix transcription factor genes Hes1 and Ngn2 are regulated by Pax3 during mouse embryonic development.
Pax3 is expressed early during embryonic development in spatially restricted domains including limb muscle, neural crest, and neural tube. Pax3 functions at the nodal point in melanocyte stem cell differentiation, cardiogenesis and neurogenesis. Additionally Pax3 has been implicated in migration and differentiation of precursor cell populations. Currently there are questions about how Pax3 regulates these diverse functions. In this study we found that in the absence of functional Pax3, as in Splotch embryos, the neural crest cells undergo premature neurogenesis, as evidenced by increased Brn3a positive staining in neural tube explants, in comparison with wild-type. Premature neurogenesis in the absence of functional Pax3 may be due to a change in the regulation of basic helix-loop-helix transcription factors implicated in proliferation and differentiation. Using promoter-luciferase activity measurements in transient co-transfection experiments and electro-mobility shift assays, we show that Pax3 regulates Hairy and enhancer of split homolog-1 (Hes1) and Neurogenin2 (Ngn2) by directly binding to their promoters. Chromatin immunoprecipitation assays confirmed that Pax3 bound to cis-regulatory elements within Hes1 and Ngn2 promoters. These observations suggest that Pax3 regulates Hes1 and Ngn2 and imply that it may couple migration with neural stem cell maintenance and neurogenesis.
Nakazaki
Hiromichi
H
Laboratory for Neural Tube Research, Developmental Biology Program, Children's Memorial Research Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60614, USA.
Reddy
Anvesh C
AC
Mania-Farnell
Barbara L
BL
Shen
Yueh-Wei
YW
Ichi
Shunsuke
S
McCabe
Christopher
C
George
David
D
McLone
David G
DG
Tomita
Tadanori
T
Mayanil
C S K
CS
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics*; D002465:Cell Movement; D047108:Embryonic Development / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D005838:Genotype; D018257:Helix-Loop-Helix Motifs / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics*; D009432:Neural Crest / Q000502:physiology; D054259:Neural Tube / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000072056:Transcription Factor HES-1
D051792:Basic Helix-Loop-Helix Proteins; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D000072056:Transcription Factor HES-1; C489734:Hes1 protein, mouse; C102938:Neurog2 protein, mouse