| Autor: |
Marino, Rita, Kimura, Yuko, De Santis, Rosaria, Lambris, John D., Pinto, Maria Rosaria |
| Předmět: |
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| Zdroj: |
Immunogenetics; Mar2002, Vol. 53 Issue 12, p1055-1064, 10p |
| Abstrakt: |
The recent identification of complement components in deuterostome invertebrates has indicated the presence of a complement system operating via an alternative pathway in echinoderms and tunicates and via a MBL-mediated pathway thus far identified only in tunicates. Here, we report the isolation of two C3-like genes, CiC3-1 and CiC3-2, from blood cell total RNA of the ascidian Ciona intestinalis. The deduced amino acid sequences of both Ciona C3-like proteins exhibit a canonical processing site for α and β chains, a thioester site with an associated catalytic histidine and a convertase cleavage site, thus showing an overall similarity to the other C3 molecules already characterized. Southern blotting analysis indicated that each gene is present as a single copy per haploid genome. In situ hybridization experiments showed that both CiC3-1 and CiC3-2 are expressed in one type of blood cell, the compartment cells. Two polyclonal antibodies, raised against two deduced peptide sequences in the α chain of CiC3-1 and CiC3-2, allowed the identification by Western blot of a single band in the blood serum, of about Mr 150,000. A phylogenetic tree, based on the alignment of CiC3-1 and CiC3-2 with molecules of the α2-macroglobulin superfamily, indicated that the Ciona C3s form a cluster with Halocynthia roretzi C3. The phylogenetic analysis also suggested that the duplication event from which the CiC3-1 and CiC3-2 genes originated occurred in the urochordate lineage after the separation of the Halocynthia and Ciona ancestor. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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