Comparative proteomic analysis of mammalian animal tissues and body fluids: bovine proteome database

Characterizing the complete proteome of multicellular organisms is a challenging task using the currently available technologies. With the increasing degree of genetic complexity, animals acquire a broader repertoire of options to meet environmental challenges. Mammalian cells from different tissues/body fluids express different thousands of proteins with a predicted dynamic range of up to five to six orders of magnitude, thus necessitating the whole arsenal of dedicated analytical strategies for a detailed proteome characterization. Nevertheless, 2D-E analysis of whole cellular lysates still remains the most used initial approach for the proteomic description of specialized cells. It enables to obtain an overview of the main soluble protein components of a specific tissue/body fluid, allowing comparison between different cellular types and molecular description of organ specialization. Massive proteomic investigations have been reported mainly in the case of human, mouse and rat, allowing comparative analysis. For this reason, a research project focused on the 2D-E characterization of tissues and biological fluids from other domestic mammals has been undertaken in our laboratory. A number of high-resolution reference electrophoretic maps have been established for liver, kidney, muscle, plasma and red blood cells samples from Holstein Friesian bovine female individuals. Among the 1863 distinct protein features detected, 534 species were identified and associated to 209 different genes by a combination of MALDI-TOF mass fingerprint, capillary LC-ESI-IT-MS-MS and image gel matching procedures. Identified polypeptide species and differences in expression profiles between various tissues/fluids clearly reflected organ biochemical specialization. This experimental output allowed establishing a 2D-E bovine database accessible at the URL address for image comparison.