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: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.