GALNT3, a gene associated with hyperphosphatemic familial tumoral calcinosis, is transcriptionally regulated by extracellular phosphate and modulates matrix metalloproteinase activity
BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE
Authors: Chefetz, Ilana; Kohno, Kimitoshi; Izumi, Hiroto; Uitto, Jouni; Richard, Gabriele; Sprecher, Eli
Abstract
GALNT3 encodes UDP-N-acetyl-alpha-D-galactosamine: polypeptide N-acetylgalactosaminyl-transferarase 3 (ppGaINacT3), a glycosyltransferase which has been suggested to prevent proteolysis of FGF23, a potent phosphaturic protein. Accordingly, loss-of-function mutations in GALNT3 cause hyperphosphatemic familial tumoral calcinosis (HFTC), a rare autosomal recessive disorder manifesting with increased kidney reabsorption of phosphate, resulting in severe hyperphosphatemia and widespread ectopic calcifications. Although these findings definitely attribute a role to ppGaINacT3 in the regulation of phosphate homeostasis, little is currently known about the factors regulating GALNT3 expression. In addition, the effect of decreased GALNT3 expression in peripheral tissues has not been explored so far. In the present study, we demonstrate that GALNT3 expression is under the regulation of a number of factors known to be associated with phosphate homeostasis, including inorganic phosphate itself, calcium and 1,25-dihydroxyvitamin D-3. In addition, we show that decreased GALNT3 expression in human skin fibroblasts leads to increased expression of FGF7 and of matrix metalloproteinases, which have been previously implicated in the pathogenesis of ectopic calcification. Thus, the present data suggest that ppGaINacT3 may play a role in peripheral tissues of potential relevance to the pathogenesis of disorders of phosphate metabolism. (C) 2008 Elsevier B.V. All rights reserved.
Genome-wide identification, phylogeny, and expression of fibroblast growth genes in common carp
GENE
Authors: Jiang, Likun; Zhang, Songhao; Dong, Chuanju; Chen, Baohua; Feng, Jingyan; Peng, Wenzhu; Mahboob, Shahid; Al-Ghanim, Khalid A.; Xu, Peng
Abstract
Fibroblast growth factors (FGFs) are a large family of polypeptide growth factors, which are found in organisms ranging from nematodes to humans. In vertebrates, a number of FGFs have been shown to play important roles in developing embryos and adult organisms. Among the vertebrate species, FGFs are highly conserved in both gene structure and amino-acid sequence. However, studies on teleost FGFs are mainly limited to model species, hence we investigated FGFs in the common carp genome. We identified 35 FGFs in the common carp genome. Phylogenetic analysis revealed that most of the FGFs are highly conserved, though recent gene duplication and gene losses do exist. By examining the copy number of FGFs in several vertebrate genomes, we found that eight FGFs in common carp have undergone gene duplications, including FGF6a, FGF6b, FGF7, FGF8b, FGF10a, FGF11b, FGF13a, and FGF18b. The expression patterns of all FGFs were examined in various tissues, including the blood, brain, gill, heart, intestine, muscle, skin, spleen and kidney, showing that most of the FGFs were ubiquitously expressed, indicating their critical role in common carp. To some extent, examination of gene families with detailed phylogenetic or orthology analysis verified the authenticity and accuracy of assembly and annotation of the recently published common carp whole genome sequences. Gene families are also considered as a unique source for evolutionary studies. Moreover, the whole set of common carp FGF gene family provides an important genomic resource for future biochemical, physiological, and phylogenetic studies on FGFs in teleosts. (C) 2015 Elsevier B.V. All rights reserved.