Journal Article

Preaxial polydactyly caused by <i>Gli3</i> haploinsufficiency is rescued by <i>Zic3</i> loss of function in mice

Malgorzata E. Quinn, Allison Haaning and Stephanie M. Ware

in Human Molecular Genetics

Volume 21, issue 8, pages 1888-1896
Published in print April 2012 | ISSN: 0964-6906
Published online January 2012 | e-ISSN: 1460-2083 | DOI: http://dx.doi.org/10.1093/hmg/dds002
Preaxial polydactyly caused by Gli3 haploinsufficiency is rescued by Zic3 loss of function in mice

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Limb anomalies are important birth defects that are incompletely understood genetically and mechanistically. GLI3, a mediator of hedgehog signaling, is a genetic cause of limb malformations including pre- and postaxial polydactyly, Pallister–Hall syndrome and Greig cephalopolysyndactyly. A closely related Gli (glioma-associated oncogene homolog)-superfamily member, ZIC3, causes X-linked heterotaxy syndrome in humans but has not been investigated in limb development. During limb development, post-translational processing of Gli3 from activator to repressor antagonizes and posteriorly restricts Sonic hedgehog (Shh). We demonstrate that Zic3 and Gli3 expression overlap in developing limbs and that Zic3 converts Gli3 from repressor to activator in vitro. In Gli3 mutant mice, Zic3 loss of function abrogates ectopic Shh expression in anterior limb buds, limits overexpression in the zone of polarizing activity and normalizes aberrant Gli3 repressor/Gli3 activator ratios observed in Gli3+/− embryos. Zic3 null;Gli3+/− neonates show rescue of the polydactylous phenotype seen in Gli3+/− animals. These studies identify a previously unrecognized role for Zic3 in regulating limb digit number via its modifying effect on Gli3 and Shh expression levels. Together, these results indicate that two Gli superfamily members that cause disparate human congenital malformation syndromes interact genetically and demonstrate the importance of Zic3 in regulating Shh pathway in developing limbs.

Journal Article.  5400 words.  Illustrated.

Subjects: Genetics and Genomics

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