Characterization of the human homologue of the mouse Tg737 candidate polycystic kidney disease gene

We previously identified a gene from the mutant locus in a new mouse mutation that causes recessive polycystic kidney disease. Here we describe the cloning, characterization and mapping of the homologous human gene. The human and mouse genes are 95% identical at the predicted amino acid sequence level, and both genes encode a putative protein that contains a tetratricopeptide repeat motif. The human gene, called hTg737, is expressed with a broad tissue distribution that includes the the kidney and liver, and gives rise to a 2.9 kb mRNA. The gene contains 26 exons and spans a genomic region greater than 100 kb. Chromosome mapping experiments revealed that the hTg737 gene maps near the centromere on the long arm of human chromosome 13, at position 13q12.1. While this gene does not map to the primary locus that has been identified for ARPKD in humans, it may represent a candidate gene for other recessive renal disorders that have yet to be mapped.

Candidate gene associated with a mutation causing recessive polycystic kidney disease in mice

A line of transgenic mice was generated that contains an insertional mutation causing a phenotype similar to human autosomal recessive polycystic kidney disease. Homozygotes displayed a complex phenotype that included bilateral polycystic kidneys and an unusual liver lesion. The mutant locus was cloned and characterized through use of the transgene as a molecular marker. Additionally, a candidate polycystic kidney disease (PKD) gene was identified whose structure and expression are directly associated with the mutant locus. A complementary DNA derived from this gene predicted a peptide containing a motif that was originally identified in several genes involved in cell cycle control.