Laboratory for Biology and Microbial Genetics, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, Pierottijeva 6, Zagreb, Croatia.
Environ Sci Pollut Res Int. 2013 Dec;20(12):8600-11. doi: 10.1007/s11356-013-1819-2. Epub 2013 May 21.
A multixenobiotic resistance (MXR) mechanism mediated by ABC binding cassette (ABC) transport proteins is an efficient chemical defence mechanism in sea urchin embryos. The aim of our work was to evidence whether exposure to sub-lethal doses of specific contaminants (oxybenzone (OXI), mercuric chloride (HgCl2) and trybutiltin (TBT)) would induce MXR transporter activity during embryonic development (from zygote to blastula stage) in purple sea urchin (Paracentrotus lividus) embryos. Further, we present data on molecular identification, transport function, expression levels and gene localisation of two ABC efflux transporters-P-glycoprotein (ABCB1/P-gp) and sulfonylurea-receptor-like protein (ABCC9/SUR-like). Partial cDNA sequences of abcb1 and abcc9 were identified and quantitative PCR (qPCR) evidenced an increase in mRNA transcript levels of both ABC transporters during the two-cell, as well as an overall decrease during the blastulae stage. Calcein-AM efflux activity assay indicated the activation of multidrug resistance-associated protein/ABCC-like transport in the presence of HgCl2 and TBT in exposed blastulae. The in situ hybridisation of the two-cell and blastula stages showed ubiquitous localisation of both transcripts within cells, supporting qPCR data. In conclusion, ABCB1 and ABCC9 are constitutive, as are HgCl2, TBT and OXI-inducible ABC membrane transporters, coexpressed in the zygote, two-cell and blastula stages of the P. lividus. Their ubiquitous cell localisation further fortifies their protective role in early embryonic development.
多药耐药（MXR）机制由 ABC 结合盒（ABC）转运蛋白介导，是海胆胚胎中一种有效的化学防御机制。我们的工作旨在证明在胚胎发育过程中（从受精卵到囊胚阶段），暴露于低剂量的特定污染物（氧苯酮（OXI）、氯化汞（HgCl2）和三丁基锡（TBT））是否会诱导紫色海胆（Paracentrotus lividus）胚胎中的 MXR 转运蛋白活性。此外，我们还提供了关于两种 ABC 外排转运蛋白-P-糖蛋白（ABCB1/P-gp）和磺酰脲受体样蛋白（ABCC9/SUR-like）的分子鉴定、转运功能、表达水平和基因定位的数据。鉴定了 abcb1 和 abcc9 的部分 cDNA 序列，定量 PCR（qPCR）表明，在受精卵和囊胚阶段，两种 ABC 转运体的 mRNA 转录水平均增加，而在囊胚阶段总体下降。钙黄绿素-AM 外排活性测定表明，在暴露于 HgCl2 和 TBT 的囊胚中，多药耐药相关蛋白/ABCC 样转运被激活。在二细胞期和囊胚期进行原位杂交，显示两种转录本在细胞内广泛存在，支持 qPCR 数据。总之，ABCB1 和 ABCC9 是组成型的，HgCl2、TBT 和 OXI 诱导的 ABC 膜转运体也是如此，在 P. lividus 的受精卵、二细胞期和囊胚期均有表达。它们在细胞内的广泛存在进一步强化了它们在早期胚胎发育中的保护作用。
