Three novel carp CXC chemokines are expressed early in ontogeny and at nonimmune sites

Three novel CXC chemokines were identified in common carp (Cyprinus carpio L.) through homology cloning. Phylogenetic analyses show that one of the three CXC chemokines is an unambiguous orthologue of CXCL14, whereas both others are orthologues of CXCL12, and were named CXCL12a and CXCL12b. Percentages of amino acid identity between each of these carp chemokines and their human and mouse orthologues are markedly higher than those reported previously for other carp CXC chemokines, suggestive of involvement in vital processes, which have allowed for relatively few structural changes. Furthermore, all three novel carp CXC chemokines are expressed during early development, in contrast to established immune CXC chemokines. In noninfected adult carp, CXCL12b and CXCL14 are predominantly expressed in the brain. CXCL12a is highly expressed in kidney and anterior kidney, but its expression is still more abundant in brain than any other carp CXC chemokine. Clearly, these chemokines must play key roles in the patterning and maintenance of the (developing) vertebrate central nervous system.