title: Cloning, expression and characterization of CCL21 and CCL25 chemokines in zebrafish.
abstract: Chemokines are a large group of proteins implicated in migration, activation, and differentiation of leukocytes. They are well-surveyed in mammals, but less is known in lower vertebrates about their spatiotemporal expressions and functions. From an evolutionary point of view, comparative analyses may provide some fundamental insights into these molecules. In mammals, CCL21 and CCL25 are crucial for thymocyte homing. Herein, we identified and cloned the zebrafish orthologues of CCL21 and CCL25, and analyzed their expression in embryos and adult fish by in situ hybridization. We found that CCL21 was expressed in the craniofacial region, pharynx, and blood vessels in embryos. In adult fish, CCL21 transcripts were located in the kidney, spinal cord, and blood cells. In contrast, expression of CCL25 was only detected in the thymus primordia in embryos. In adult fish, transcripts of CCL25 were maintained in the thymus, and they were also found in the brain and oocytes. Furthermore, we performed an antisense oligonucleotide experiment to evaluate the biological function of CCL25. Results showed that the recruitment of thymocytes was impeded by morpholino-mediated knockdown of CCL25, suggesting that CCL25 is essential for colonization of T-cells in the thymus in early development. Together, our results demonstrate the basic profiles of two CCL chemokines in zebrafish. The tissue-specific expression patterns may pave the way for further genetic dissection in this model organism.
authors: Graduate Institute of Oral Biology, School of Dentistry, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC.
authors: I-Na
authors: IN
authors: Lu
authors: Bor-Luen
authors: BL
authors: Chiang
authors: Kuo-Long
authors: KL
authors: Lou
authors: Po-Tsang
authors: PT
authors: Huang
authors: Chung-Chen Jane
authors: CC
authors: Yao
authors: Juo-Song
authors: JS
authors: Wang
authors: Li-Deh
authors: LD
authors: Lin
authors: Jiiang-Huei
authors: JH
authors: Jeng
authors: Bei-En
authors: BE
authors: Chang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D054421:Chemokine CCL21 / Q000737:chemistry / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D019742:Chemokines, CC / Q000737:chemistry / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D003001:Cloning, Molecular; D004625:Embryo, Nonmammalian / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D010802:Phylogeny; D016415:Sequence Alignment; D013950:Thymus Gland / Q000196:embryology / Q000378:metabolism; D059467:Transcriptome; D015027:Zebrafish / Q000196:embryology / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D029961:Zebrafish Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology / Q000378:metabolism
chemical_list: D054421:Chemokine CCL21; D019742:Chemokines, CC; D029961:Zebrafish Proteins; C576691:ccl25a protein, zebrafish; C576692:ccl25b protein, zebrafish