In silico cloning and digital differential display analysis of Danio rerio QM gene by EST database searching

QM homologs, associated with tumor suppression, cell growth, differentiation, development and apoptosis, were isolated from human and many other organisms. However, QM derived from fish was not reported. Through integrated analysis of public database such as EST, TIGR Gene Index in silico, a full-length eDNA encoding QM homologue of human QM protein was identified from Danio rerio, which is 769 bp length and has a putative protein of 215 amino acids with a predicted mol. wt. of 24.6 kD and isoelectric point of 10.6. It was found that Danio rerio QM amino acid sequence includes 1 Ribosomal protein L10e signature, 2 Amidation sites, 1 Tyrosine sulfation site, 1 N-myristoylation site and 1 Protein kinase C phosphorylation site by scanning PROSITE motifs. The Danio rerio QM shares an 66% - 92% amino acid sequence identical to other proteins of the QM family, including human etc, respectively. Study showed that Danio rerio QM gene expressed in all Danio rerio embryo and adult tissues by digital differential display based on UinGene. The experiment provided us with a feasible bioinformatics method for cloning new functional genes, thereby preparing for further research on fish QM gene function.