Oliveira Marisa M, Shingleton Alexander W, Mirth Christen K
Development, Evolution and the Environment Laboratory, Instituto Gulbenkian de Ciência, Oeiras, Portugal.
Dept. of Zoology, Michigan State University, East Lansing, Michigan, United States of America; Dept. of Biology, Lake Forest College, Lake Forest, Illinois, United States of America.
PLoS Genet. 2014 Jun 19;10(6):e1004408. doi: 10.1371/journal.pgen.1004408. eCollection 2014 Jun.
Development produces correctly patterned tissues under a wide range of conditions that alter the rate of development in the whole body. We propose two hypotheses through which tissue patterning could be coordinated with whole-body development to generate this robustness. Our first hypothesis states that tissue patterning is tightly coordinated with whole-body development over time. The second hypothesis is that tissue patterning aligns at developmental milestones. To distinguish between our two hypotheses, we developed a staging scheme for the wing imaginal discs of Drosophila larvae using the expression of canonical patterning genes, linking our scheme to three whole-body developmental events: moulting, larval wandering and pupariation. We used our scheme to explore how the progression of pattern changes when developmental time is altered either by changing temperature or by altering the timing of hormone synthesis that drives developmental progression. We found the expression pattern in the wing disc always aligned at moulting and pupariation, indicating that these key developmental events represent milestones. Between these milestones, the progression of pattern showed greater variability in response to changes in temperature and alterations in physiology. Furthermore, our data showed that discs from wandering larvae showed greater variability in patterning stage. Thus for wing disc patterning, wandering does not appear to be a developmental milestone. Our findings reveal that tissue patterning remains robust against environmental and physiological perturbations by aligning at developmental milestones. Furthermore, our work provides an important glimpse into how the development of individual tissues is coordinated with the body as a whole.
在广泛的条件下，发育过程能产生模式正确的组织，这些条件会改变全身的发育速率。我们提出了两个假说，通过它们可以使组织模式形成与全身发育相协调，从而产生这种稳健性。我们的第一个假说指出，随着时间的推移，组织模式形成与全身发育紧密协调。第二个假说是，组织模式形成在发育里程碑处对齐。为了区分这两个假说，我们利用经典模式形成基因的表达，为果蝇幼虫的翅成虫盘开发了一种分期方案，并将我们的方案与三个全身发育事件联系起来：蜕皮、幼虫游走和化蛹。我们使用我们的方案来探究当发育时间通过改变温度或改变驱动发育进程的激素合成时间而改变时，模式的进展情况。我们发现翅成虫盘中的表达模式总是在蜕皮和化蛹时对齐，这表明这些关键的发育事件代表了里程碑。在这些里程碑之间，模式的进展在对温度变化和生理改变的响应中表现出更大的变异性。此外，我们的数据表明，来自游走幼虫的成虫盘在模式形成阶段表现出更大的变异性。因此，对于翅成虫盘的模式形成来说，游走似乎不是一个发育里程碑。我们的研究结果表明，组织模式形成通过在发育里程碑处对齐，对环境和生理干扰保持稳健。此外，我们的工作为个体组织的发育如何与整个身体协调提供了重要的见解。
