Cloning and characterization of the human ameloblastin gene

We isolated the full-length human ameloblastin (AMBN) cDNA clone using reve rse transcription-polymerase chain reaction (RT-PCR) methods. Sequence anal ysis of the AMEN cDNA revealed an open reading frame of 1341 bp encoding a 447-amino acid protein. Comparison with pig, cattle, rat, and mouse AMEN se quences showed a high amino acid sequence similarity and led to the identif ication of a novel 78 bp (26 amino acids) insert resulting from internal se quence duplication. By DNA analysis of a human genomic clones, the AMEN gen e was shown to consist of 13 exons and a novel 78 bp segment, which proved to comprise two small exons. Human ameloblastomas express AMBN transcripts that contain some mutations. (C) 2000 Elsevier Science B.V. All rights rese rved.