Breakdown of abdominal patterning in the Tribolium Kruppel mutant jaws
Breakdown of abdominal patterning in the Tribolium Kruppel mutant jaws
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DOI：
10.1242/dev.02154
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发表时间：
2005-12-01
期刊：
影响因子：
4.6
通讯作者：
Klingler, M
中科院分区：
文献类型：
--
作者：
Cerny, AC;Bucher, G;Klingler, M
在果蝇的分割过程中，间隙基因作为短程梯度起作用，决定了配对规则条纹的边界。一个经典的例子是果蝇Kruppel（Dm'Kr），其在合胞胚盘胚胎的中间表达。Dm ′ Kr突变体中的图案缺陷对称地集中在其钟形表达谱周围。我们分析了Kruppel在短胚芽甲虫赤拟谷盗中的作用，其中对应于10个腹部节的配对规则条纹出现在胚盘之后的生长阶段。我们表明，以前描述的突变颚是一个无定形Tc'Kr等位基因。胚盘中的配对规则基因表达在无定形突变体和Tc'Kr RNAi胚胎中都不受影响。只有在随后的胚芽带生长过程中，配对规则模式才会被破坏。然而，只有在Tc ′ Kr表达结构域之后出现的片段受到影响，即缺失谱相对于表达结构域是不对称的。此外，条纹形成在后腹节中不恢复，即Tc ′ Kr-颌表型不构成节形成中的间隙，而是由超过第5夜条纹的分割的破裂引起的。Tc'Ki（jaws）突变体中成对规则基因表达的改变并不表明Tc'Kr在定义果蝇中特定条纹边界中的直接作用。总之，这些发现表明，Kruppel在这种短胚昆虫中的分割功能与其在果蝇长胚胚胎中的作用有根本的不同。然而，Tc'Kr在Hox基因调控中的作用更符合果蝇范例。
During Drosophila segmentation, gap genes function as short-range gradients that determine the boundaries of pair-rule stripes. A classical example is Drosophila Kruppel (Dm'Kr) which is expressed in the middle of the syncytial blastoderm embryo. Patterning defects in Dm'Kr mutants are centred symmetrically around its bell-shaped expression profile. We have analysed the role of Kruppel in the short-germ beetle Tribolium castaneum where the pair-rule stripes corresponding to the 10 abdominal segments arise during growth stages subsequent to the blastoderm. We show that the previously described mutation jaws is an amorphic Tc'Kr allele. Pair-rule gene expression in the blastoderm is affected neither in the amorphic mutant nor in Tc'Kr RNAi embryos. Only during subsequent growth of the germ band does pair-rule patterning become disrupted. However, only segments arising posterior to the Tc'Kr expression domain are affected, i.e. the deletion profile is asymmetric relative to the expression domain. Moreover, stripe formation does not recover in posterior abdominal segments, i.e. the Tc'Kr-jaws phenotype does not constitute a gap in segment formation but results from a breakdown of segmentation past the 5th eve stripe. Alteration of pair-rule gene expression in Tc'Ki(jaws) mutants does not suggest a direct role of Tc'Kr in defining specific stripe boundaries as in Drosophila. Together, these findings show that the segmentation function of Kruppel in this short-germ insect is fundamentally different from its role in the long-germ embryo of Drosophila. The role of Tc'Kr in Hox gene regulation, however, is in better accordance to the Drosophila paradigm.