Glucokinase thermolability and hepatic regulatory protein binding are essential factors for predicting the blood glucose phenotype of missense mutations.

To better understand how glucokinase (GK) missense mutations associated with human glycemic diseases perturb glucose homeostasis, we generated and characterized mice with either an activating (A456V) or inactivating (K414E) mutation in the gk gene. Animals with these mutations exhibited alterations in their blood glucose concentration that were inversely related to the relative activity index of GK. Moreover, the threshold for glucose-stimulated insulin secretion from islets with either the activating or inactivating mutation were left- or right-shifted, respectively.

Multiallelic disruption of the rictor gene in mice reveals that mTOR complex 2 is essential for fetal growth and viability.

The rapamycin-insensitive mTOR complex 2 (mTORC2) has been suggested to play an important role in growth factor-dependent signaling. To explore this possibility further in a mammalian model system, we disrupted the expression of rictor, a specific component of mTORC2, in mice by using a multiallelic gene targeting strategy. Embryos that lack rictor develop normally until E9.

Strategies for the use of site-specific recombinases in genome engineering.

Conventional gene targeting has been very useful in the study of gene function and regulation in mice. However, the methodologies involved have several limitations. First, mutations that cause embryonic lethality largely preclude studies of gene function at a later stage in development.

Efficient DNA cassette exchange in mouse embryonic stem cells by staggered positive-negative selection.

Recombinase-mediated cassette exchange (RMCE), when applied to mouse embryonic stem (ES) cells, promises to increase the ease with which genetic alterations can be introduced into targeted genomic loci in the mouse. However, existing selection strategies for identifying ES cells in which replacement DNA cassettes from a carrier plasmid have been exchanged correctly into a defined locus are suboptimal. Here, we report the generation in mouse ES cells of a loxed cassette acceptor (LCA) allele within the glucokinase (gk) gene locus.

Sulfonylurea receptor type 1 knock-out mice have intact feeding-stimulated insulin secretion despite marked impairment in their response to glucose.

The ATP-sensitive potassium channel is a key molecular complex for glucose-stimulated insulin secretion in pancreatic beta cells. In humans, mutations in either of the two subunits for this channel, the sulfonylurea type 1 receptor (Sur1) or Kir6.2, cause persistent hyperinsulinemic hypoglycemia of infancy.