Zic1 regulates the patterning of vertebral arches in cooperation with Gli3

Skeletal abnormalities are described that appeared in Zic1-deficient mice, These mice show multiple abnormalities in the axial skeleton, The deformiti es are severe in the dorsal parts of the vertebrae, vertebral arches, but l ess so in the vertebral bodies (spina bifida occulta). The proximal ribs ar e deformed having ectopic processes. The abnormalities found in the vertebr al arches can be traced back to disturbed segmental patterns of dorsal scle rotome, The Zic1/Gli3 double mutants showed severe abnormalities of vertebr al arches not found in single mutants, The abnormalities in the vertebral a rches were less severe in Zic1/Pax1 mutants than Zic1/Gli3 mutants, but sig nificantly more pronounced than in Zic1 single mutants. The three genes may act synergistically in the development of the vertebral arches. (C) 1999 E lsevier Science Ireland Ltd. All rights reserved.