Send to

Choose Destination
Immunogenetics. 2005 Aug;57(7):535-48. Epub 2005 Sep 29.

Characterization of a C3-like cDNA in a coral: phylogenetic implications.

Author information

Department of Biological Sciences, Florida International University, University Park Campus, 11200 SW 8th Street, Miami, FL 33199, USA.


C3, C4, and C5 are thiolester-containing proteins (TEPs) of vertebrate complement. The identification of the molecular origin of the TEP family, and more specifically the ancestor protein of complement components C3, C4, and C5, remains a fundamental question. The prevailing paradigm suggests that duplication and divergence of these proteins occurred after the deuterostome split in phylogeny. It is believed that the ancestor of thiolester-containing complement proteins was alpha-2-macroglobulin (A2M)-like, a noncomplement-related protein. Here we describe a C3-like cDNA from a gorgonian coral, Swiftia exserta. This study provides evidence for the origins of a complement-related C3-like gene in the Precambrian period, predating both protostomes and deuterostomes. Furthermore, one may speculate that complement-like opsonic reactions were evolving at the earliest stages of metazoan evolution. This calls for a reassessment of the present concepts concerning the origins and evolution of TEPs.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Springer
Loading ...
Support Center