PMC

Illustration of a class 1 domain (A) and a class 2 domain (B) encoded by four exons. The different types of introns and exons in the coding sequence of class 2 domains (as used in the analysis of intron phases) are indicated (see text for details).

Intron-phase combinations of the discoidin domain in 10 human genes representing 7 gene families (A–G). Boxes represent the discoidin domain (a) and its neighboring domains (b–i) (not drawn to scale). Numbers indicate the phase class of the introns. Phase 1 introns found at the boundaries of the discoidin domain are shown in boldface. The seven different Ensembl gene families (http://www.ensembl.org) are as follows: (A) endothelial and muscle cell-derived neuropilin-like protein, (B) lactadherin milk fat globule EGF factor, (C) neuropilin precursor vascular endothelial cell growth factor, (D) carboxypeptidase H, (E) contactin-associated protein like, (F) discoidin domain receptor, and (G) coagulation factor VIII precursor. The letters within the boxes refer to the following Pfam signatures: discoidin domain (a), EGF-like domain (b), CUB domain (c), MAM domain (d), zinc carboxypeptidase (e), laminin G type domain (f), fibrinogen carboxy-terminal globular domain (g), protein kinase domain (h), and multicopper oxidase (i).