Localization and identification of the mutant gene in the loop-tail mouse / 中国比较医学杂志

Objective To define the loci of the mutant gene in the loop-tail mouse.Methods To study the heredity pattern, loop-tail mice were mated with normal C57BL/6J and C3H mice.Their offsprings with loop-tail or normal phenotype were registered respectively.Microsatellite marker D1Mit113 and D1Mit149 were used to locate the mutant gene.Based on fine mapping, the candidate gene Vangl2 was found.Vangl2 gene from the loop-tail mice was amplified by PCR followed by sequencing.Incision enzyme FspBI ( BfaI ) identified the genotype of offspring from loop-tail mice intercrossing.Results Heredity test indicated that the loop-tail phenotype was controlled by a single dominant gene not with 100%penetrance but was affected by genetic background.A C-to-T transversion was at the 1345bp in Vangl2 gene of the loop-tail mice.Conclusions The C-to-T transversion introduces a pre-termination codon of amino acids and causes the phenotype of loop-tail phenotype.None homozygous mice were found in the offsprings, suggesting that the homozygous mice are lethal.

Planar cell polarity pathway regulates nephrin endocytosis in developing podocytes.

The noncanonical Wnt/planar cell polarity (PCP) pathway controls a variety of cell behaviors such as polarized protrusive cell activity, directional cell movement, and oriented cell division and is crucial for the normal development of many tissues. Mutations in the PCP genes cause malformation in multiple organs. Recently, the PCP pathway was shown to control endocytosis of PCP and non-PCP proteins necessary for cell shape remodeling and formation of specific junctional protein complexes. During formation of the renal glomerulus, the glomerular capillary becomes enveloped by highly specialized epithelial cells, podocytes, that display unique architecture and are connected via specialized cell-cell junctions (slit diaphragms) that restrict passage of protein into the urine; podocyte differentiation requires active remodeling of cytoskeleton and junctional protein complexes. We report here that in cultured human podocytes, activation of the PCP pathway significantly stimulates endocytosis of the core slit diaphragm protein, nephrin, via a clathrin/ß-arrestin-dependent endocytic route. In contrast, depletion of the PCP protein Vangl2 leads to an increase of nephrin at the cell surface; loss of Vangl2 functions in Looptail mice results in disturbed glomerular maturation. We propose that the PCP pathway contributes to podocyte development by regulating nephrin turnover during junctional remodeling as the cells differentiate.