No abstract

The mRNA expression and localization of the aquaporin (AQP) family in rat kidney were examined by ribonuclease protection assay and immunohistochemistry. AQP1, AQP2, AQP3, and AQP4 mRNA were hardly detectable in 16-day gestation fetuses. AQP1 mRNA was explosively expressed at 1 wk, keeping the level throughout life. AQP2 mRNA expression was apparently noticed in 18-day fetuses and was enhanced gradually with age to reach a plateau at 4 wk. AQP3 and AQP4 mRNA expression was significantly found at birth but was not changed remarkably thereafter. AQP2 protein appeared first at the apical side of collecting duct cells in 18-day fetuses. The staining intensity at the site increased with age, and basolateral staining was added in adult rats. AQP3 was distinctly demonstrated at the basolateral side of collecting duct cells after birth, and the staining intensity was almost stable throughout life. The progressive induction of AQP2 expression in the first 4 wk after birth is presumed to contribute to the maturation of urinary concentrating capacity during the kidney development.

BackgroundMarbling defined by the amount and distribution of intramuscular fat, so-called Shimofuri, is an economically important trait of beef cattle in Japan. The c17-25 expressed sequence tag (EST) has been previously shown to possess expression difference in musculus longissimus muscle between low-marbled and high-marbled steer groups, and to be located within genomic region of a quantitative trait locus for marbling. Thus, the akirin 2 (AKIRIN2) gene containing the c17-25 EST sequence was considered as a positional functional candidate for the gene responsible for marbling. In this study, we explored single nucleotide polymorphism (SNP) in the AKIRIN2 and analyzed association of the SNP with marbling.FindingsA SNP in the 3' untranslated region of the AKIRIN2, referred to as c.*188G>A, was the only difference detected between high- and low-marbled steer groups. The SNP was associated with marbling in 3 experiments using 100 sires (P = 0.041), 753 paternal half-sib progeny steers from 4 sires heterozygous for the c.*188G>A (P = 0.005), and 730 paternal half-sib progeny steers from 3 sires homozygous for the A allele at the c.*188G>A (P = 0.047), in Japanese Black beef cattle. The effect of genotypes of the SNP on subcutaneous fat thickness was not statistically significant (P > 0.05).ConclusionThese findings suggest that the AKIRIN2 SNP polymorphism is associated with marbling and may be useful for effective marker-assisted selection to increase the levels of marbling in Japanese Black beef cattle.

Omodysplasia-2 (OMOD2; OMIM%16475) is a rare autosomal dominant (AD) skeletal dysplasia characterized by shortened humeri, short first metacarpal, craniofacial dysmorphism (frontal bossing, depressed nasal bridge, bifid nasal tip, and long philtrum), and variable degrees of genitourinary anomalies. This clinical phenotype overlaps with that of AD type Robinow syndrome. Recently, a mutation in FZD2 encoding a Frizzled Class Receptor 2 has been identified in a family with AD omodysplasia (an affected girl and her affected mother). Here, we present the second report on a heterozygous novel nonsense FZD2 mutation in OMOD2 or Robinow syndrome-like phenotype. The proband was a 16-year-old boy, who has been followed from infancy to adolescence. He presented with rhizomelic short stature with elbow restriction, mild facial dysmorphism (depressed broad bridge, short nose, anteverted nostrils, long philtrum, and low-set ears), and genital hypoplasia. Radiological examination in infancy showed short, broad humeri with relatively narrow distal ends, mildly broad femora, thick proximal ulnae with hypoplastic, dislocated proximal radii, and short first metacarpals. The abnormal skeletal pattern was persistent in adolescence; however, the humeri and femora became less undermodeled, while the humeri and radii became mildly bowed. Molecular analysis identified a de novo, heterozygous, nonsense mutation (c.1640C>A, p.S547*) in FZD2. The affected codon was next to the previously reported mutation (p.Trp548*). The results indicate that OMOD2 or Robinow syndome-like phenotype can be caused by a heterozygous nonsense FZD2 mutation impairing Wnt signaling. Further molecular studies will permit better clarification of the phenotypic spectrum in patients with OMOD2.

BackgroundMarbling defined by the amount and distribution of intramuscular fat is an economically important trait of beef cattle in Japan. We have recently reported that single nucleotide polymorphisms (SNPs) in the endothelial differentiation, sphingolipid G-protein-coupled receptor, 1 (EDG1) gene were associated with marbling in Japanese Black beef cattle. As well as EDG1, the titin (TTN) gene, involved in myofibrillogenesis, has been previously shown to possess expression difference in musculus longissimus muscle between low-marbled and high-marbled steer groups, and to be located within genomic region of a quantitative trait locus for marbling. Thus TTN was considered as a positional functional candidate for the gene responsible for marbling. In this study, we explored SNP in TTN and analyzed association of the SNP with marbling.FindingsA SNP in the promoter region of TTN, referred to as g.231054C>T, was the only difference detected between high- and low-marbled steer groups. The SNP was associated with marbling in 3 experiments using 101 sires (P = 0.004), 848 paternal half-sib progeny steers from 5 sires heterozygous for the g.231054C>T (P = 0.046), and 820 paternal half-sib progeny steers from 3 sires homozygous for C allele at the g.231054C>T (P = 0.051), in Japanese Black beef cattle. The effect of genotypes of the SNP on subcutaneous fat thickness was not statistically significant (P > 0.05).ConclusionThese findings suggest that in addition to the EDG1 SNPs, the TTN SNP polymorphism is associated with marbling and may be useful for effective marker-assisted selection to increase the levels of marbling in Japanese Black beef cattle. Further replicate studies will be needed to confirm the allelic association observed here, and to expand the results to evaluate all possible genotypic combinations of alleles.