1. A novel ZRS variant causes preaxial polydactyly type I by increased sonic hedgehog expression in the developing limb bud
- Author
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Xu, Caixia, Yang, Xiaoming, Zhou, Hang, Li, Yongyong, Xing, Chao, Zhou, Taifeng, Zhong, Dongmei, Lian, Chengjie, Yan, Mei, Chen, Tao, Liao, Zhiheng, Gao, Bo, Su, Deying, Wang, Tingting, Sharma, Swarkar, Mohan, Chandra, Ahituv, Nadav, Malik, Sajid, Li, Quan-Zhen, and Su, Peiqiang
- Subjects
Human Genome ,Genetics ,2.1 Biological and endogenous factors ,Aetiology ,Animals ,Caco-2 Cells ,Disease Models ,Animal ,Female ,Gene Knock-In Techniques ,HEK293 Cells ,Hedgehog Proteins ,Heterogeneous-Nuclear Ribonucleoprotein K ,Humans ,Introns ,Limb Buds ,Male ,Membrane Proteins ,Mice ,Mice ,Transgenic ,Pedigree ,Polydactyly ,Polymorphism ,Single Nucleotide ,Thumb ,Up-Regulation ,preaxial polydactyly ,ZRS ,sonic hedgehog ,gene regulation ,Clinical Sciences ,Genetics & Heredity - Abstract
PurposePreaxial polydactyly (PPD) is a common congenital hand malformation classified into four subtypes (PPD I-IV). Variants in the zone of polarizing activity regulatory sequence (ZRS) within intron 5 of the LMBR1 gene are linked to most PPD types. However, the genes responsible for PPD I and the underlying mechanisms are unknown.MethodsA rare large four-generation family with isolated PPD I was subjected to genome-wide genotyping and sequence analysis. In vitro and in vivo functional studies were performed in Caco-2 cells, 293T cells, and a knockin transgenic mouse model.ResultsA novel g.101779T>A (reference sequence: NG_009240.2; position 446 of the ZRS) variant segregates with all PPD I-affected individuals. The knockin mouse with this ZRS variant exhibited PPD I phenotype accompanying ectopic and excess expression of Shh. We confirmed that HnRNP K can bind the ZRS and SHH promoters. The ZRS mutant enhanced the binding affinity for HnRNP K and upregulated SHH expression.ConclusionOur results identify the first PPD I disease-causing variant. The variant leading to PPD I may be associated with enhancing SHH expression mediated by HnRNP K. This study adds to the ZRS-associated syndromes classification system for PPD and clarifies the underlying molecular mechanisms.
- Published
- 2020