Project description:Major urinary proteins (MUP) are the major component of the urinary protein fraction in house mice (Mus spp.) and rats (Rattus spp.). The structure, polymorphism and functions of these lipocalins have been well described in the western European house mouse (Mus musculus domesticus), clarifying their role in semiochemical communication. The complexity of these roles in the mouse raises the question of similar functions in other rodents, including the Norway rat, Rattus norvegicus. Norway rats express MUPs in urine but information about specific MUP isoform sequences and functions is limited. In this study, we present a detailed molecular characterization of the MUP proteoforms expressed in the urine of two laboratory strains, Wistar Han and Brown Norway, and wild caught animals, using a combination of manual gene annotation, intact protein mass spectrometry and bottom-up mass spectrometry-based proteomic approaches. Detailed sequencing of the urinary MUP isoforms reveals a less complex pattern of primary sequence polymorphism in the rat than the mouse. However, rat MUPs exhibit added complexity in the form of post-translational modifications, including the phosphorylation of Ser4 in some isoforms, and exoproteolytic trimming of specific isoforms.
Project description:The Goto-Kakizak (GK) rat, a nonobese animal model of Type 2 diabetes (T2D), were developed by repeated inbreeding of glucose-intolerent individuals selected from Wistar rats. During their development, GK rats suffer from reduced beta-cell mass and insulin resistance spontaneously (T2D phenotype), which are supposed to be caused by loci holding different genotypes between GK and Wistar rats. This array CGH experiment can detect loci which show different copy numbers (genotype) between GK and Wistar rats. These loci serve as a valuable repository for mining candidates contributing to the pathogenesis of T2D.
