Project description:We have used dietary administration of stable isotope labelled lysine to assess protein turnover rates for proteins from four tissues in the bank vole, Myodes glareolus. The annotated genome for this species is not available, so protein identification was attained through cross-species matching to the mouse. For proteins for which confident identifications were derived, the pattern of lysine incorporation over 40d was used to define the rate of synthesis of individual proteins in the four tissues. The data were heavily filtered to retain a very high quality data-set of turnover rates for 1088 proteins. Comparative analysis of the four tissues revealed different median rates of degradation (kidney: 0.099 per day; liver 0.136 per day; heart, 0.054 per day and skeletal muscle, 0.035 per day). These data were compared with protein degradation rates from other studies on intact animals or from cells in culture.
Project description:The urine of bank voles (Myodes glareolus) contains substantial quantities of a small protein that is expressed at much higher levels in males than females, and at higher levels in males in the breeding season. This protein was purified and completely sequenced at the protein level by mass spectrometry. Leucine/isoleucine ambiguity was completely resolved by metabolic labelling, monitoring the incorporation of dietary deuterated leucine into specific sites in the protein. The predicted mass of the sequenced protein was exactly consonant with the mass of the protein measured in bank vole urine samples, correcting for the formation of two disulphide bonds. The sequence of the protein revealed that it was a lipocalin related to aphrodisin and other odorant binding proteins (OBPs), but differed from all OBPs previously described. The pattern of secretion in urine used for scent marking by male bank voles, and similarity to other lipocalins used as chemical signals in rodents, suggest that this protein plays a role in male sexual and/or competitive communication. We propose the name glareosin for this novel protein to reflect the origin of the protein and to emphasise the distinction from known OBPs.
Project description:The water vole Arvicola terrestris (= Arvicola amphibious L.) is endemic in Europe where its outbreak generates severe economic losses for farmers. Our project aimed at deciphering the modalities of chemical communication in this species, to develop new sustainable methods for populations control. The water vole, as well as other rodents, uses specific urination sites as territorial and sex pheromone markers, the chemical and biochemical identification of which is still unknown. Lateral scent glands and urine samples were collected from wild males and females caught in the field, at different periods of the year. Volatile signals were searched in urine by SPME/GC-MS, and in lateral scent glands by solvent extraction followed by GC-MS. The volatile composition of urine was analysed for each individual and not on pooled samples, showing no significant difference between males and females. Lateral scent glands contained some volatile components (pyrazines, alcohols, terpenes), and mostly long chain fatty acid esters, again without quantitative and qualitative differences between sexes. Conversely, the urinary protein content, analysed by 1D- and 2D-electrophoresis is different, as only males secrete high levels of lipocalins, whatever the reproduction period. The proteins were identified by mass spectrometry and “de novo” analysis (Orbitrap), which provided specific information to design primers for PCR amplification of cDNA sequences. Thus, urinary proteins were characterized by direct amplification from liver RNA. The identified protein sequences are closed to those of Myodes glareolus, a closely related species of Cricetidae, and to hamster Aphrodisin.