Mutations in LGI1 cause autosomal-dominant partial epilepsy with auditory features.

The epilepsies are a common, clinically heterogeneous group of disorders defined by recurrent unprovoked seizures. Here we describe identification of the causative gene in autosomal-dominant partial epilepsy with auditory features (ADPEAF, MIM 600512), a rare form of idiopathic lateral temporal lobe epilepsy characterized by partial seizures with auditory disturbances. We constructed a complete, 4.2-Mb physical map across the genetically implicated disease-gene region, identified 28 putative genes (Fig. 1) and resequenced all or part of 21 genes before identifying presumptive mutations in one copy of the leucine-rich, glioma-inactivated 1 gene (LGI1) in each of five families with ADPEAF. Previous studies have indicated that loss of both copies of LGI1 promotes glial tumor progression. We show that the expression pattern of mouse Lgi1 is predominantly neuronal and is consistent with the anatomic regions involved in temporal lobe epilepsy. Discovery of LGI1 as a cause of ADPEAF suggests new avenues for research on pathogenic mechanisms of idiopathic epilepsies.     

An obesity-associated gut microbiome with increased capacity for energy harvest

The worldwide obesity epidemic is stimulating efforts to identify host and environmental factors that affect energy balance. Comparisons of the distal gut microbiota of genetically obese mice and their lean littermates, as well as those of obese and lean human volunteers have revealed that obesity is associated with changes in the relative abundance of the two dominant bacterial divisions, the Bacteroidetes and the Firmicutes. Here we demonstrate through metagenomic and biochemical analyses that these changes affect the metabolic potential of the mouse gut microbiota. Our results indicate that the obese microbiome has an increased capacity to harvest energy from the diet. Furthermore, this trait is transmissible: colonization of germ-free mice with an 'obese microbiota' results in a significantly greater increase in total body fat than colonization with a 'lean microbiota'. These results identify the gut microbiota as an additional contributing factor to the pathophysiology of obesity.     

Deficiency of UBR1, a ubiquitin ligase of the N-end rule pathway, causes pancreatic dysfunction, malformations and mental retardation (Johanson-Blizzard syndrome)

Johanson-Blizzard syndrome (OMIM 243800) is an autosomal recessive disorder that includes congenital exocrine pancreatic insufficiency, multiple malformations such as nasal wing aplasia, and frequent mental retardation. We mapped the disease-associated locus to chromosome 15q14-21.1 and identified mutations, mostly truncating ones, in the gene UBR1 in 12 unrelated families with Johanson-Blizzard syndrome. UBR1 encodes one of at least four functionally overlapping E3 ubiquitin ligases of the N-end rule pathway, a conserved proteolytic system whose substrates include proteins with destabilizing N-terminal residues. Pancreas of individuals with Johanson-Blizzard syndrome did not express UBR1 and had intrauterine-onset destructive pancreatitis. In addition, we found that Ubr1(-/-) mice, whose previously reported phenotypes include reduced weight and behavioral abnormalities, had an exocrine pancreatic insufficiency, with impaired stimulus-secretion coupling and increased susceptibility to pancreatic injury. Our findings indicate that deficiency of UBR1 perturbs the pancreas' acinar cells and other organs, presumably owing to metabolic stabilization of specific substrates of the N-end rule pathway.     

The origins and uses of mouse outbred stocks

Outbred mouse stocks, often used in genetics, toxicology and pharmacology research, have been generated in rather haphazard ways. Understanding the characteristics of these stocks and their advantages and disadvantages is important for experimental design. In many studies these mice are used inappropriately, wasting animals' lives and resources on suboptimal experiments. Recently, however, researchers from the field of complex trait analysis have capitalized on the genetics of outbred stocks to refine the identification of quantitative trait loci. Here we assess the most widely used outbred stocks of mice and present guidelines for their use.     

Modes of variation in alcohol dehydrogenase inDrosophila melanogaster

Zusammenfassung Neben zwei elektrophoretisch verschiedenen Varianten derDrosophila-Alkoholdehydrogenase kommen innerhalb dieser Varianten weitere Variationen vor, die sich in ihrer spezifischen Aktivität und Temperaturempfindlichkeit unterscheiden. Es wird daraus geschlossen, dass der Grad des Polymorphismus von Populationen grösser sei, als aufgrund elektrophoretischer Untersuchungen geschätzt wird.     

In vitro interaction of enkephalin with serum and chromaffin granule components

Summary Incubation of radioactively labeled enkephalin with serum components or chromaffin granule components in vitro provided evidence that there are specific constituents which bind enkephalins and may affect their degradation. Evidence for carboxy-terminal degradation was found.This work was supported by the NIH Grants NS-13201 and NS-00201.