Genomic organization, alternative splicing, and multiple regulatory regions of the zebrafish fgf8 gene
Genomic organization, alternative splicing, and multiple regulatory regions of the zebrafish fgf8 gene
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DOI：
10.1111/j.1440-169x.2006.00882.x
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发表时间：
2006-09-01
影响因子：
2.5
通讯作者：
Yamasu, Kyo
中科院分区：
文献类型：
--
作者：
Inoue, Fumitaka;Nagayoshi, Saori;Yamasu, Kyo
FGF8是成纤维细胞生长因子家族的成员之一，在脊椎动物的发育中起着关键作用。本研究克隆了斑马鱼Fgf8基因的基因组DNA，以阐明该基因在脊椎动物胚胎中时空受限表达的调控机制。结构分析表明，Fgf8的外显子-内含子组织在从硬骨鱼到哺乳动物的脊椎动物进化过程中高度保守。对基因组序列的仔细检查和逆转录-聚合酶链式反应分析发现，斑马鱼Fgf8编码两个剪接变体，对应于哺乳动物中已知的四到七个剪接变体，分别对应于Fgf8a和Fgf8b。两个变异体在注射后的斑马鱼胚胎中的错误表达表明，两个变异体对斑马鱼胚胎都有背部作用，其中Fgf8b的作用更强。对斑马鱼Fgf8转录调控的报告基因分析表明，其复杂的表达模式是由基因上下游不同调控区的组合介导的，这被认为是斑马鱼Fgf8在发育中发挥多重作用所必需的。此外，对不同脊椎动物Fgf8基因组序列的比较表明，这种调控机制在脊椎动物进化过程中是保守的。
Fgf8 is among the members of the fibroblast growth factor (FGF) family that play pivotal roles in vertebrate development. In the present study, the genomic DNA of the zebrafish fgf8 gene was cloned to elucidate the regulatory mechanism behind the temporally and spatially restricted expression of the gene in vertebrate embryos. Structural analysis revealed that the exon-intron organization of fgf8 is highly conserved during vertebrate evolution, from teleosts to mammals. Close inspection of the genomic sequence and reverse transcription-polymerase chain reaction analysis revealed that zebrafish fgf8 encodes two splicing variants, corresponding to Fgf8a and Fgf8b, among the four to seven splicing variants known in mammals. Misexpression of the two variants in zebrafish embryos following mRNA injection showed that both variants have dorsalizing activities on zebrafish embryos, with Fgf8b being more potent. Reporter gene analysis of the transcriptional regulation of zebrafish fgf8 suggested that its complicated expression pattern, which is considered essential for its multiple roles in development, is mediated by combinations of different regulatory regions in the upstream and downstream regions of the gene. Furthermore, comparison of the genomic sequence of fgf8 among different vertebrate species suggests that this regulatory mechanism is conserved during vertebrate evolution.