Identification of Potential Peroxisomal Proteins in Mouse

First, we analyzed the FANTOM2 cDNA collection for the presence of peroxins (Pex), the proteins that are essential for peroxisome biogenesis. So far, 24 PEX genes have been characterized in yeast. Of these, BLAST analysis of FANTOM2 RTPS revealed 13 PEX genes conserved in mouse (PEX1, PEX2, PEX3, PEX5, PEX6, PEX7, PEX10, PEX11, PEX12, PEX13, PEX14, PEX16, and PEX19). By comparison with the human, the coverage of PEX proteins in the mouse FANTOM2 set is complete, as human homologs have been found so far for the same set of 13 PEX genes. Second, to identify new peroxisomal proteins, we searched RTPS for ORFs that contain the carboxy-terminal peroxisome-targeting signal S/AKL (PTS1). In addition to 23 previously known PTS1-containing peroxisomal proteins, this analysis identified 5 putative new proteins that could be targeted to the organelles.