Murine expressed sequence tags (EST) showing homology with chondromodulin-I (ChM-I) were identified. Cloning of the full-length cDNA revealed a novel protein (317 amino acid residues) having a domain homologous to ChM-I, and we termed it tenodmoulin (TeM). The predicted amino acid sequence revealed 33% overall identity with mouse ChM-I precursor. Overall structural features were conserved well in TeM, including a single transmembrane domain at the N-terminal region and the putative antiangiogenic domain with eight cysteine residues. However, TeM lacked a hormone-processing signal present in the ChM-I precursor, suggesting that it may function as a type II transmembrane protein on cell surface. TeM transcript (1.4 kb in size) was detected in skeletal muscle by Northern blot analysis. In situ hybridization analysis revealed that the expression of TeM mRNA was not associated with muscle fibers, but was tightly associated with epimysium and tendon, both of which are classified as dense connective tissue having little vascularity.