The human OSM (oncostatin M) gene is involved in regulation of cell growth. It regulates cytokine production, and is involved in the maturation of fetal hepatocytes. The OSM protein stimulates proliferation of Kaposi's sarcoma cells in HIV-infected individuals.
Imagine that you are working with the OSM gene, studying effects of mutation on the protein sequence. You would like to know what the cDNA sequence looks like, to make targetted mutations in the DNA that will code for alternate amino acids. You can use Ensembl to search for the OSM gene and find answers to these questions.