CRISPR/Cas9 Mutagenesis Reveals Versatile Roles of Hox Genes in Crustacean Limb Specification and Evolution
CRISPR/Cas9 Mutagenesis Reveals Versatile Roles of Hox Genes in Crustacean Limb Specification and Evolution
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DOI：
10.1016/j.cub.2015.11.021
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发表时间：
2016-01-11
期刊：
影响因子：
9.2
通讯作者：
Patel, Nipam H.
中科院分区：
文献类型：
--
作者：
Martin, Arnaud;Serano, Julia M.;Patel, Nipam H.
甲壳类动物拥有各种各样的特化肢体。虽然Hox基因表达结构域的变化已被假定在产生这种肢体多样性中发挥作用，但几乎没有功能数据来了解Hox基因在甲壳动物发育过程中的确切作用。我们使用CRISPR/Cas9靶向突变和RNAi敲低的组合来破译在片足类Parhyale hawaiensis发育中的嘴和躯干中表达的六个Hox基因的功能。这些实验操纵的动物显示出特异的和惊人的同源异型转化。我们发现，腹部-A（abd-A）和腹部-B（abd-B）是正确的后部模式所必需的，敲除Abd-B导致动物具有胸部型腿，沿着原本是腹部的腿，而abd-A中断产生简化的身体计划，其特征在于腹部和胸部附件的专业化丧失。在胸部，UBX是必要的鳃发育和抑制的gnathal的命运，和Antp决定爪形态。在口腔中，Scr和Antp赋予部分颚，部分胸部混合身份的上颌，和Scr和Dfd防止触角身份在头部后段。我们的研究结果使我们能够定义的作用Hox基因在指定每个附属物类型Parhyale，包括模块化的性质，其中一些附属物的图案由Hox基因输入。此外，我们定义如何在Hox基因表达的变化产生了甲壳类物种之间的形态差异。最后，我们还强调了基于CRISPR/Cas9的体细胞诱变在新兴模式生物中的实用性。
Crustaceans possess a diverse array of specialized limbs. Although shifts in Hox gene expression domains have been postulated to play a role in generating this limb diversity, little functional data have been provided to understand the precise roles of Hox genes during crustacean development. We used a combination of CRISPR/Cas9-targeted mutagenesis and RNAi knockdown to decipher the function of the six Hox genes expressed in the developing mouth and trunk of the amphipod Parhyale hawaiensis. These experimentally manipulated animals display specific and striking homeotic transformations. We found that abdominal-A (abd-A) and Abdominal-B (Abd-B) are required for proper posterior patterning, with knockout of Abd-B resulting in an animal with thoracic type legs along what would have been an abdomen, and abd-A disruption generating a simplified body plan characterized by a loss of specialization in both abdominal and thoracic appendages. In the thorax, Ubx is necessary for gill development and for repression of gnathal fate, and Antp dictates claw morphology. In the mouth, Scr and Antp confer the part-gnathal, part-thoracic hybrid identity of the maxilliped, and Scr and Dfd prevent antennal identity in posterior head segments. Our results allow us to define the role Hox genes play in specifying each appendage type in Parhyale, including the modular nature by which some appendages are patterned by Hox gene inputs. In addition, we define how changes in Hox gene expression have generated morphological differences between crustacean species. Finally, we also highlight the utility of CRISPR/Cas9-based somatic mutagenesis in emerging model organisms.