Zebrafish cdx1b regulates expression of downstream factors of Nodal signaling during early endoderm formation
Zebrafish cdx1b regulates expression of downstream factors of Nodal signaling during early endoderm formation
复制标题
DOI：
10.1242/dev.010595
复制
发表时间：
2008-03-01
期刊：
影响因子：
4.6
通讯作者：
Hwang, Sheng-Ping L.
中科院分区：
文献类型：
--
作者：
Cheng, Pei-Yi;Lin, Chia-Chi;Hwang, Sheng-Ping L.
我们确定了一个斑马鱼尾部相关的同源异型盒（cdx 1b）基因，该基因与人类和小鼠cdx 1基因具有同线保守性。斑马鱼cdx 1b转录本是母系沉积的。从原肠胚形成晚期到1-2S期，CDX 1b在上胚层和下胚层细胞中均匀表达，并且可以在18-22 HPF期的视网膜、脑和体节中鉴定。在发育28小时后，cdx 1b只在发育中的肠道中表达。进行反义吗啉代寡核苷酸介导的敲低和过表达实验以分析cdx 1b功能。在96只hpf cdx 1b突变体中观察到肝脏和胰腺发育不良以及肠道异常。在85%的epiboly cdx 1b morphants中，鉴定出表达gata 5-，cas-，foxa 2-和sox 17-的内胚层前体的数量分别减少了两倍。此外，异位cdx 1b的表达导致大量增加的相应数量的gata 5-，cas-，foxa 2-和sox 17-表达内胚层前体和改变其分布模式，在85%的epiboly注射胚胎。保守的Cdx 1结合基序被确定在两个gata 5和foxa 2基因种间序列比较。Cdx 1b可以结合到Cdx 1结合基序位于内含子1的foxa 2基因的基础上的电泳迁移率变动分析。共注射斑马鱼或小鼠foxa 2 mRNA与cdx 1b MO拯救了53 hpf注射胚胎肝脏中铜蓝蛋白的表达结构域。这些结果表明，斑马鱼cdx 1b调节foxa 2的表达，也可能调节gata 5的表达，从而影响早期内胚层的形成。这项研究强调了一个新的作用，斑马鱼cdx 1b在不同的消化器官的发展相比，其哺乳动物同源物。
We identified a zebrafish caudal-related homeobox (cdx1b) gene, which shares syntenic conservation with both human and mouse Cdx1. Zebrafish cdx1b transcripts are maternally deposited. cdx1b is uniformly expressed in both epiblast and hypoblast cells from late gastrulation to the 1-2s stages and can be identified in the retinas, brain and somites during 18-22 hpf stages. After 28 hours of development, cdx1b is exclusively expressed in the developing intestine. Both antisense morpholino oligonucleotide-mediated knockdown and overexpression experiments were conducted to analyze cdx1b function. Hypoplastic development of the liver and pancreas and intestinal abnormalities were observed in 96 hpf cdx1b morphants. In 85% epiboly cdx1b morphants, twofold decreases in the respective numbers of gata5-, cas-, foxa2- and sox17-expressing endodermal precursors were identified. Furthermore, ectopic cdx1b expression caused substantial increases in the respective numbers of gata5-, cas-, foxa2- and sox17-expressing endodermal precursors and altered their distribution patterns in 85% epiboly injected embryos. Conserved Cdx1-binding motifs were identified in both gata5 and foxa2 genes by interspecific sequence comparisons. Cdx1b can bind to the Cdx1-binding motif located in intron 1 of the foxa2 gene based on an electrophoretic mobility shift assay. Co-injection of either zebrafish or mouse foxa2 mRNA with the cdx1b MO rescued the expression domains of ceruloplasmin in the liver of 53 hpf injected embryos. These results indicate that zebrafish cdx1b regulates foxa2 expression and may also modulate gata5 expression, thus affecting early endoderm formation. This study underscores a novel role of zebrafish cdx1b in the development of different digestive organs compared with its mammalian homologs.