Right atrial isomerism (RAI) is a heterotaxy syndrome with disturbances in the left–right axis development, resulting in complex heart malformations and abnormal lateralization of other thoracic and abdominal organs. Although autosomal-recessive inheritance of heterotaxy syndrome is seen in multiple families, underlying gene defects have remained unknown. Here we identify the molecular genetic basis of a kindred with five siblings with RAI. Linkage analysis and positional candidate gene approach showed that the affected children were compound heterozygotes for truncating mutations in the growth/differentiation factor 1 (GDF1) gene. Individuals heterozygous for the mutations were clinically healthy. This finding, supported by the similar phenotype in Gdf1 knockout mouse, provides firm evidence that RAI can occur as a recessively inherited condition, with GDF1 as the culprit gene. The results will shed light on the biological basis of human laterality defects and facilitate molecular diagnosis of RAI.
Bacterial heat-labile (LT) enterotoxins signal through tightly regulated interactions with host cell gangliosides. LT-IIa and LT-IIb of Escherichia coli bind preferentially to gangliosides with a NeuAcα2-3Galβ1-3GalNAc terminus, with key distinctions in specificity. LT-IIc, a newly discove ... mehr
Phosphate deficiency is characteristic for many natural habitats, resulting in different physiological responses in plants and bacteria including the replacement of phospholipids by glycolipids and other phosphorous-free lipids. The plant pathogenic bacterium Agrobacterium tumefaciens, whi ... mehr
A tryptophan side chain was introduced into subsite +1 of family GH-18 (class V) chitinases from Nicotiana tabacum and Arabidopsis thaliana (NtChiV and AtChiC, respectively) by the mutation of a glycine residue to tryptophan (G74W-NtChiV and G75W-AtChiC). The specific activity toward glyco ... mehr