Research
| Title： | Divergent Expression Patterns and Function of Two cxcr4 Paralogs in Hermaphroditic Epinephelus coioides |
|---|---|
| First author： | Lu, Wei-Jia; Zhou, Li; Gao, Fan-Xiang; Sun, Zhi-Hui; Li, Zhi; Liu, Xiao-Chun; Li, Shui-Sheng; Wang, Yang; Gui, Jian-Fang |
| Journal： | INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES |
| Years： | 2018 |
| DOI： | 10.3390/ijms19102943 |
| Abstract： | Chemokine receptor Cxcr4 evolved two paralogs in the teleost lineage. However, cxcr4a and cxcr4b have been characterized only in a few species. In this study, we identified two cxcr4 paralogs from the orange-spotted grouper, Epinephelus coioides. The phylogenetic relationship and gene structure and synteny suggest that the duplicated cxcr4a/b should result from the teleost-specific genome duplication (Ts3R). The teleost cxcr4 gene clusters in two paralogous chromosomes exhibit a complementary gene loss/retention pattern. Ec_cxcr4a and Ec_cxcr4b show differential and biased expression patterns in grouper adult tissue, gonads, and embryos at different stages. During embryogenesis, Ec_cxcr4a/b are abundantly transcribed from the neurula stage and mainly expressed in the neural plate and sensory organs, indicating their roles in neurogenesis. Ec_Cxcr4a and Ec_Cxcr4b possess different chemotactic migratory abilities from the human SDF-1, Ec_Cxcl12a, and Ec_Cxcl12b. Moreover, we uncovered the N-terminus and TM5 domain as the key elements for specific ligand-receptor recognition of Ec_Cxcr4a-Ec_Cxcl12b and Ec_Cxcr4b-Ec_Cxcl12a. Based on the biased and divergent expression patterns of Eccxcr4a/b, and specific ligand-receptor recognition of Ec_Cxcl12a/b-Ec_Cxcr4b/a, the current study provides a paradigm of sub-functionalization of two teleost paralogs after Ts3R. |
