Differential regulation of p53 function by the N-terminal ΔNp53 and Δ113p53 isoforms in zebrafish embryos.
Differential regulation of p53 function by the N-terminal ΔNp53 and Δ113p53 isoforms in zebrafish embryos.
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DOI：
10.1186/1471-213x-10-102
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发表时间：
2010-10-07
影响因子：
--
通讯作者：
Rodeck U
中科院分区：
文献类型：
--
作者：
Davidson WR;Kari C;Ren Q;Daroczi B;Dicker AP;Rodeck U
p53蛋白家族协调细胞和生物体的应激反应。p53 mRNA的替代启动子使用和/或剪接产生至少9种具有不同N-和C-末端的哺乳动物p53蛋白，其在正常和恶性细胞中差异表达。人N-末端p53变体包含全长（FL）或截短的（ΔN/Δ40）或完全没有反式激活结构域（Δ133）。不同的p53亚型共表达的功能后果是不明确的。在此，我们研究了斑马鱼Δ Np 53直系同源物在发育胚胎中共表达的FLp 53和斑马鱼Δ 133 p53直系同源物（Δ 113 p53）的功能方面。我们克隆了斑马鱼Δ Np 53亚型，并确定电离辐射增加了斑马鱼胚胎中稳态Δ Np 53和Δ 113 p53 mRNA水平的表达。通过mRNA注射的异位Δ Np 53表达引起头部、眼睛和体节的发育不全和畸形，但部分抵消了伴随FLp 53表达引起的致死效应。FLp 53的表达是Δ Np 53引起的发育畸变和细胞周期蛋白依赖性激酶抑制剂1A（CDKN 1A，p21，Cip 1，WAF 1）的Δ Np 53依赖性表达所必需的。p21表达的敲低显著降低了与Δ Np 53过表达相关的发育畸形的严重程度。相反，强制Δ 113 p53表达对Δ Np 53依赖的胚胎表型几乎没有影响。这些功能属性在斑马鱼和在斑马鱼胚胎中异位表达的人Δ Np 53直系同源物之间共享。所有3种斑马鱼异构体转染Saos 2细胞后可以相互免疫共沉淀。这两种替代的N端p53亚型在发育中的斑马鱼中表达，以响应细胞应激，并在不同程度上拮抗FLp 53的致死效应。然而，与Δ 113 p53相反，强制Δ Np 53表达本身导致发育缺陷，这部分依赖于p21反式激活。与FLp 53相反，Δ Np 53引起的发育异常并不被Δ 113 p53的伴随表达所抵消。
The p53 protein family coordinates stress responses of cells and organisms. Alternative promoter usage and/or splicing of p53 mRNA gives rise to at least nine mammalian p53 proteins with distinct N- and C-termini which are differentially expressed in normal and malignant cells. The human N-terminal p53 variants contain either the full-length (FL), or a truncated (ΔN/Δ40) or no transactivation domain (Δ133) altogether. The functional consequences of coexpression of the different p53 isoforms are poorly defined. Here we investigated functional aspects of the zebrafish ΔNp53 ortholog in the context of FLp53 and the zebrafish Δ133p53 ortholog (Δ113p53) coexpressed in the developing embryo. We cloned the zebrafish ΔNp53 isoform and determined that ionizing radiation increased expression of steady-state ΔNp53 and Δ113p53 mRNA levels in zebrafish embryos. Ectopic ΔNp53 expression by mRNA injection caused hypoplasia and malformation of the head, eyes and somites, yet partially counteracted lethal effects caused by concomitant expression of FLp53. FLp53 expression was required for developmental aberrations caused by ΔNp53 and for ΔNp53-dependent expression of the cyclin-dependent kinase inhibitor 1A (CDKN1A, p21, Cip1, WAF1). Knockdown of p21 expression markedly reduced the severity of developmental malformations associated with ΔNp53 overexpression. By contrast, forced Δ113p53 expression had little effect on ΔNp53-dependent embryonal phenotypes. These functional attributes were shared between zebrafish and human ΔNp53 orthologs ectopically expressed in zebrafish embryos. All 3 zebrafish isoforms could be coimmunoprecipitated with each other after transfection into Saos2 cells. Both alternative N-terminal p53 isoforms were expressed in developing zebrafish in response to cell stress and antagonized lethal effects of FLp53 to different degrees. However, in contrast to Δ113p53, forced ΔNp53 expression itself led to developmental defects which depended, in part, on p21 transactivation. In contrast to FLp53, the developmental abnormalities caused by ΔNp53 were not counteracted by concomitant expression of Δ113p53.