Fig. 1. Molecular characterization of the SPRR4 gene and protein. (A) Physical map of the SPRR4 gene in the SPRR locus. Three overlapping cosmid clones (South et al., 1999) are represented. Black boxes indicate either the genomic sequences of individual genes or the SPRR2 cluster as a whole. EcoRI restriction sites (E) are indicated. (B) Nucleotide and deduced amino acid sequence of the SPRR4 gene. The sequence used as a probe is underlined, and the position of the single intron is indicated by an asterisk. Grey boxes indicate the four internal octapeptide repeats. Putative polyadenylation sites are double underlined. GenBank accession number AF335109. (C) Comparison of internal repeat consensi from the two groups (I/II) and four classes of human SPRR proteins (Cabral et al., 2001). The number of repetitive units for each class is represented between brackets. Amino acids conserved in three out of four classes are in red. (D) Amino acid sequence of N- and C-terminal SPRR domains. Differences between various classes are in bold. Amino acids involved in the transglutaminase mediated crosslinking reaction in SPRR1, -2 or -3, and conserved in SPRR4, are in red.
