Extensive expansion and diversification of the chemokine gene family in zebrafish: Identification of a novel chemokine subfamily CX

Abstract

Background: The chemokine family plays important roles in cell migration and activation. In humans, at least 44 members are known. Based on the arrangement of the four conserved cysteine residues, chemokines are now classified into four subfamilies, CXC, CC, XC and CX3C. Given that zebrafish is an important experimental model and teleost fishes constitute an evolutionarily diverse group that forms half the vertebrate species, it would be useful to compare the zebrafish chemokine system with those of mammals. Prior to this study, however, only incomplete lists of the zebrafish chemokine genes were reported.

Phylogenetic analysis of vertebrate CXC chemokines reveals novel lineage specific groups in teleost fish

“…The CC and CXC chemokine family are the two largest groups, containing multiple members, whilst the CX 3 C and XC family consist of one or two members respectively. More recently a fish specific CX subfamily has been described in zebrafish (Nomiyama et al, 2008), with four members present.…”

“…Teleost fish appear to have an even larger repertoire of chemokines possibly due to an extra round of genome duplication, with 111 chemokines identified recently in the zebrafish genome, the majority of which (81 genes) belong to the CC family (Alejo and Tafalla, 2011;Nomiyama et al, 2008). Despite the conserved two pairs of cysteine residues seen in the CC and CXC family, the primary sequences of the chemokines are highly divergent, making it extremely difficult to determine the phylogenetic relationships among family members during evolution (Nomiyama et al, 2008;DeVries et al, 2006;Peatman and Liu, 2007;Laing and Secombes, 2004). Therefore, it has been problematic to establish a common nomenclature for some chemokines from early vertebrates simply based on the phylogenetic classification in mammals.…”

The integrative roles of chemokines at the maternal–fetal interface in early pregnancy

“…The fifth receptor subfamily, CX, reported only in zebrafish lacks the two N-terminal residues, but retains the third and fourth residues. 4 The CXC family can be further subdivided by the presence or absence of a conserved 'Glu-Leu-Arg' (ELR) subsequence at the NH2 terminus. The ELR 1 family is involved in angiogenesis and the ELR 2 family is involved in angiostatic activity.…”

Arche de Noé immunologique

“…Les principaux membres de la famille de l'IL-1 (IL-1α, -1β, -18) existent également [26]. Une très grande diversité de chimiokines a été identifiée [27]. Enfin, plusieurs homologues du TNFα (tumor necrosis factor) et du TGFβ (transforming growth factor) sont également présents.…”