斑馬魚酪胺酸磷酸水解酶 (ptp4a1 & ptp4a2) 在胚胎早期的功能分析

Abstract

Protein tyrosine phosphatase 4A (ptp4a) family not only affect cell growth, division, migration and differentiation but serve as a “biomarker” of cancer in recent studies. Instead of only one type (PRL-1) in vertebrates, ptp4a family contains three members (ptp4a1, ptp4a2, and ptp4a3) with high sequence similarities. In this study, we focused on zebrafish ptp4a1 and ptp4a2 genes sharing 81% similarity. We performed in situ hybridization to observe the expression of ptp4a1 and ptp4a2 during zebrafish embryonic development. ptp4a1 was abundant from 12-hpf to 3-dpf, and mainly found in brain (tectum, tegmentum, telencephalon, diencephalon, mesencephalon, cerebellum, and metencephalon), eyes (retinal pigment epithelium, iris, outer plexiform layer, inner plexiform layer and nerve fiber layer), otic vesicle, and fin. On the other hand, ptp4a2 was abundant from 1-cell stage to 3-dpf, and was mainly distributed in myocardium, liver, fin, gut, myotomes, pronephric duct, pneumatic duct, swim bladder, arch and the outer region of the lens. Upon injection of antisense morpholino (ptp4a1-MO or ptp4a2-MO), pericardial edema and cell accumulation were observed in ptp4a1 or ptp4a2 knockdown embryos. Furthermore, co-injection of ptp4a1-MO and ptp4a2-MO resulted in even more significant defect. Heart malformation was revealed in ptp4a1/2 double knockdown embryos, based on immunostaining with muscle-specific F59 antibody and in situ hybridization with heart-specific cmlc2 probe. On the other hand, ptp4a1/2 double knockdown would result in disrupted neuromast development. In addition, such knockdown would decrease cell proliferation, but not lead to apoptosis. In summary, ptp4a1 and ptp4a2 showed differential expression patterns in zebrafish embryos: ptp4a1 was mainly found in brain and eyes, whereas ptp4a1 was mainly observed in muscle, heart, liver, gut and internal organs. Our knockdown data revealed that ptp4a1 and ptp4a2 affected cell proliferation and migration, leading to defects in zebrafish heart and neuromast development.