Another chance to cut teeth
Tooth development is a series of complex pathways where interplay of proteins directs the precise timing of events. Among these, ameloblastin is a key protein that controls the elongation of enamel crystals and directs enamel mineralisation. Partners from the Hebrew University in Jerusalem under the umbrella of the MATRIX project devised a novel protocol to obtain a high yield sample of pure ameloblastin. A new gene construct was produced with human cDNA (complementary DNA) encoding for the entire protein. Attached was a terminal His (histidine) tag required for the purification process and a honeybee signal peptide for efficient secretion in insect cells. The gene construct was cloned into a baculovirus and the recombinant protein was then produced in fall armyworm moth cells. After plaque purification, one viral clone was selected on the basis of the most efficient production rate. Cell viability, infection ratio and post-infection time were all factors used to choose the superior clone. Advantages of the method include the fact that the secreted recombinant carries the same modifications as naturally secreted ameloblastin. However, it is free of the signal peptide incorporated for efficient production. Furthermore, only one rapid step for the purification process is involved. Many proteins are involved in tooth development including amelogenin and tuftelin. The protocol developed can be applied to the mass production of these proteins also. Amelogenin is particularly important comprising 90\;% of the protein in developing enamel. Obvious applications are in the area of prosthodontics for the replacement of missing teeth.
