PRJNA260448
A Developmental Genomic Analysis of Pax1 and Pax9 in Embryonic Intervertebral Disc Development
Pax1 and Pax9 play redundant, synergistic functions in the patterning and differentiation of the sclerotomal cells that give rise to the vertebral bodies and intervertebral discs (IVD) of the axial skeleton. Gene expression profiling of an enriched population of Pax1/Pax9-expressing cells of the embryonic IVD revealed that Pax1 and Pax9 regulate cell proliferation, cartilage development, collagen fibrillogenesis and other processes vital in early IVD morphogenesis. Twenty-nine of the Pax1/Pax9 targets are also associated with axial skeletal defects that phenocopy Pax1/Pax9-deficient mice. Pax1 likely auto-regulates itself and is up-regulated in the absence of Pax9, clarifying how it compensates for the loss of Pax9, while Pax9 is unaffected by the loss of Pax1. Pax1 and Pax9 positively regulate several of the cartilage development genes known to be regulated by the “Sox trio” (Sox5/Sox6/Sox9).