title: DMP1 and DSPP: evidence for duplication and convergent evolution of two SIBLING proteins.
abstract: Since first being proposed as a tandem gene family in 2001, the relatedness of the 5 SIBLING proteins (BSP, DMP1, DSPP, MEPE, and SPP1/OPN) has predominantly depended on arguments involving shared intron/exon properties as well as conserved protein biochemical properties (e.g. unstructured and acidic) and specific peptide motifs (e.g. phosphorylation and integrin-binding RGD). This report discusses the evidence that an ancient DMP1 gene underwent a simple duplication in the common ancestor of mammals and reptiles and then separately evolved into DSPP-like paralogs in the 2 classes. Genomic sequence analyses show that different copies of the original DMP1 duplication process were selected by mammalian and reptilian (anole lizard) classes to acquire genetically different but biochemically similar phosphoserine-rich repeat domains by convergent evolution. Mammals, for example, expanded phosphoserine motifs encoded exclusively using motifs containing AGC/T serine codons while the reptile line's repeats also used TCN-encoding serine codons. A similar analysis of the origins of the other 4 SIBLINGs will require even more detailed analysis as genome sequences of various fish and amphibia become available.
authors.affiliation: Matrix Biochemistry Section, Craniofacial and Skeletal Diseases Branch, NIDCR, NIH, DHHS, Bethesda, Md, USA. lfisher@dir.nidcr.nih.gov
authors.forename: Larry W
authors.initials: LW
authors.lastname: Fisher
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002415:Cats; D019143:Evolution, Molecular; D020440:Gene Duplication / Q000235:genetics*; D008116:Lizards / Q000235:genetics; D008969:Molecular Sequence Data; D053495:Osteopontin / Q000737:chemistry / Q000235:genetics*; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics*; D017434:Protein Structure, Tertiary
chemical_list: D010750:Phosphoproteins; D053495:Osteopontin