Thursday 18 February 2010
Mutations in the homeobox gene HNF1B are associated with human diseases MODY5 (maturity-onset diabetes of the young, type V) and familial GCKD (glomerulocystic kidney disease).
In an insertional mutagenesis screen in zebrafish, we isolated mutant alleles of HNF1B (vhnf1).
Phenotypes of these mutants include formation of kidney cysts, underdevelopment of the pancreas and the liver, and reduction in size of the otic vesicles.
These abnormalities arise from patterning defects during development. We further provide evidence that vhnf1 regulates the expression of key patterning genes for these organs.
vhnf1 is required for the proper expression of pdx1 and shh (sonic hedgehog) in the gut endoderm, pax2 and wt1 in the pronephric primordial, and valentino (val) in the hindbrain.
Complementary to the loss-of-function phenotypes, overexpression of vhnf1 induces expansion of the val expression domain in the hindbrain.
vhnf1 could control development of multiple organs through regulating regional specification of organ primordia.
The similarity between vhnf1-associated fish phenotypes and human symptoms suggests a correlation between developmental functions of vhnf1 and the molecular etiology of MODY5 and GCKD.
vhnf1, the MODY5 and familial GCKD-associated gene, regulates regional specification of the zebrafish gut, pronephros, and hindbrain. Sun Z, Hopkins N. Genes Dev. 2001 Dec 1;15(23):3217-29. PMID: #11731484#