Unraveling the evolutionary origin of ELR motif using fish CXC chemokine CXCL8

Comparative Characterization of Two cxcl8 Homologs in Oplegnathus fasciatus: Genomic, Transcriptional and Functional Analyses

“…When CXCL8 orthologs of L2 from cyprinids were also included in the evolutionary analyses, they were closely placed with mammalian counterparts within the tetrapod CXCL8 cluster ( Figure S3 ), as reported in previous studies [ 14 , 23 ]. Our results suggest that L3 is closer to the ancestor of CXCL8 (i.e., slowly-evolving), in contrast to the rapidly evolving L1, which is evolutionarily closer to recently evolved tetrapod CXCL8 orthologs, and this is in agreement with the hypothesis proposed by Gangele et al [ 70 ].…”

“…As a consequence of its importance, all the tetrapod CXCL8 orthologs possess this characteristic ELR motif. In contrast to tetrapod CXCL8s, as found in many other reported teleostean CXCL8s [ 70 ], OfCXCL8s possessed ELR motif variants, EMH and NSH tripeptide sequences in OfCXCL8-L1 and OfCXCL8-L3, respectively. Among all the teleost CXCL8s characterized, homologs with the ELR motif have only been reported in haddock [ 71 ], Atlantic cod [ 34 ] and Siberian sturgeon [ 31 ].…”

“…Evidence has been clearly established for the existence of three distinct CXCL8 lineages in teleosts [ 11 , 14 , 15 , 18 , 23 , 24 , 25 , 70 ]. A recent study performed detailed evolutionary analyses and suggested that two sub-lineages are present within CXCL8-L1 [ 70 ].…”

“…Evidence has been clearly established for the existence of three distinct CXCL8 lineages in teleosts [ 11 , 14 , 15 , 18 , 23 , 24 , 25 , 70 ]. A recent study performed detailed evolutionary analyses and suggested that two sub-lineages are present within CXCL8-L1 [ 70 ]. Analysis of two cyprinoid genomes, including zebrafish and carp [ 14 , 24 , 72 ], revealed a cyprinoid-specific CXCL8 lineage 2 (CXCL8-L2), and based on evidence; a gene-specific sub-functionalization was proposed [ 14 ].…”

“…Our study adds a member to the recently identified growing L3 that already had CXCL8 orthologs from large yellow croaker [ 26 ] and rainbow trout [ 11 ]. Based on evolutionary evidence, a study has demonstrated the correlation between ELR-like motif and CXCL8 lineages [ 70 ]. It has been proposed that ancestral ELR-like motif in fish had evolved from the GGR motif of lamprey, and subsequent evolution progressed in two distinct directions to generate a motif with a consensus sequence of (a) EXH/R in L1 (e.g., ELR, DLR) and (b) NXH/R in L3 [ 70 ].…”