Polarised expression of FoxB and FoxQ2 genes during development of the hydrozoan Clytia hemisphaerica
Polarised expression of FoxB and FoxQ2 genes during development of the hydrozoan Clytia hemisphaerica
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DOI：
10.1007/s00427-006-0103-6
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发表时间：
2006-11-01
影响因子：
2.4
通讯作者：
Houliston, Evelyn
中科院分区：
文献类型：
--
作者：
Chevalier, Sandra;Martin, Arnaud;Houliston, Evelyn
我们已经表征了编码从水螅动物（Leptomedusa）Clytia hemisphaerica 中鉴定出的含有叉头盒（“Fox”）转录因子的四个基因的表达。系统发育分析包括所有可用的非两侧对称动物 Fox 序列，将这些基因置于亚科 B、Q2（两个基因）和 O 中，并表明至少 17 个 Fox 亚科存在于共同的刺胞动物/两侧对称动物祖先中，随后在刺胞动物谱系中多次丢失。脊索动物 FoxB 和 FoxQ2A 亚家族基因在早期胚胎中表现出极化表达。相应地，Clytia CheFoxB 表达位于囊胚和原肠胚阶段的原肠胚形成位点（未来的口极）周围，而 CheFoxQ2a 在互补的 aboral 结构域中表达，并在幼虫发育过程中得以维持。在幼虫内胚层区域以及水母的静囊、性腺和触手球中观察到了 CheFoxB 的明显后期表达域。第二个 Clytia FoxQ2 基因 CheFoxQ2b 在胚胎、幼虫或息肉中不表达，仅在水母的性腺中检测到。相比之下，CheFoxO 的序列表明 PI3 激酶/PKB 信号通路的调节与两侧对称动物发育调节中的已知作用一致，在整个 Clytia 生命周期中都被检测到。 CheFoxO 表达在与生长控制相关的区域（包括幼虫极、性腺和水母钟边缘）增强。这些结果支持这样的观点，即涉及 FoxB 和 FoxQ2 家族基因的早期胚胎模式系统在进化上是保守的，并表明 Fox 家族基因在水螅生命周期的其他阶段也获得了独特的作用。
We have characterised the expression of four genes coding for Forkhead box-containing (' Fox ') transcription factors identified from the hydrozoan (Leptomedusa) Clytia hemisphaerica. Phylogenetic analyses including all available non-bilaterian Fox sequences placed these genes in subfamilies B, Q2 (two genes) and O, and indicated that at least 17 Fox subfamilies were present in the common cnidarian/bilaterian ancestor, with multiple subsequent losses in cnidarian lineages. Chordate FoxB and FoxQ2A subfamily genes show polarised expression in early embryos. Correspondingly, Clytia CheFoxB expression was localised around the gastrulation site (future oral pole) at blastula and gastrula stages, with CheFoxQ2a expressed in a complementary aboral domain, maintained through larval development. Distinct later expression domains were observed for CheFoxB in the larval endoderm region, and in the statocyst, gonad and tentacle bulb of the medusa. A second Clytia FoxQ2 gene, CheFoxQ2b, not expressed in the embryo, larva or polyp, was detected uniquely in the gonads of the medusa. In contrast, CheFoxO, whose sequence indicates regulation by the PI3-Kinase/PKB signalling pathway consistent with known roles in bilaterian developmental regulation, was detected throughout the Clytia life cycle. CheFoxO expression was enhanced in regions associated with growth control including larval poles, gonad and the margin of the medusa bell. These results support the idea that an early embryonic patterning system involving FoxB and FoxQ2 family genes has been evolutionary conserved and indicate that Fox family genes have also acquired distinct roles during other phases of the hydrozoan life cycle.