A precise Bicoid gradient is nonessential during cycles 11-13 for precise patterning in the Drosophila blastoderm.
A precise Bicoid gradient is nonessential during cycles 11-13 for precise patterning in the Drosophila blastoderm.
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DOI：
10.1371/journal.pone.0003651
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发表时间：
2008
期刊：
影响因子：
3.7
通讯作者：
Ismagilov, Rustem F.
中科院分区：
文献类型：
--
作者：
Lucchetta, Elena M.;Vincent, Meghan E.;Ismagilov, Rustem F.
在发育过程中，胚胎将母体形态发生素输入解码为高度精确的合子基因表达。形态发生素 Bicoid 的发现及其对果蝇胚胎发育编程的深远影响，已成为理解母体输入解码的基石。 Bicoid 被描述为一种经典的形态发生素，通过扩散沿胚胎前后轴形成浓度梯度，并在合胞体胚层中以浓度依赖性方式启动靶基因的表达。最近的工作强调了 Bicoid 梯度作为卵长度函数的稳定性以及核动力学在维持 Bicoid 梯度中的作用。观察到 Bicoid 和核动力学，但在之前使用的理想条件下未进行调节。因此，尚未明确测试细胞化之前是否需要时间稳定的 Bicoid 梯度来实现精确图案化。在这里，我们使用微流体装置中不同温度的层流来调节核动力学和 Bicoid 梯度，以确定细胞化之前 Bicoid 梯度的稳定性对于精确图案化是否至关重要。在细胞化之前观察到细胞质和细胞核的剧烈运动，并且 Bicoid 梯度被核运动破坏，并且作为卵长度的函数高度异常。尽管在第 11-13 个周期期间出现了异常的 Bicoid 梯度，但这些胚胎中的偶数跳跃模式仍然精确。这些结果表明，在合胞体胚层阶段，Bicoid 梯度作为卵长度函数的稳定性并不重要。此外，推测在卵长度尺度上简单扩散形成的梯度不能解释所观察到的稳健的前后图案，因为严重的细胞质和核运动会破坏这种梯度。讨论了胚胎如何感知其尺寸并解释 Bicoid 梯度的其他机制。
During development, embryos decode maternal morphogen inputs into highly precise zygotic gene expression. The discovery of the morphogen Bicoid and its profound effect on developmental programming in the Drosophila embryo has been a cornerstone in understanding the decoding of maternal inputs. Bicoid has been described as a classical morphogen that forms a concentration gradient along the antero-posterior axis of the embryo by diffusion and initiates expression of target genes in a concentration-dependent manner in the syncytial blastoderm. Recent work has emphasized the stability of the Bicoid gradient as a function of egg length and the role of nuclear dynamics in maintaining the Bicoid gradient. Bicoid and nuclear dynamics were observed but not modulated under the ideal conditions used previously. Therefore, it has not been tested explicitly whether a temporally stable Bicoid gradient prior to cellularization is required for precise patterning. Here, we modulate both nuclear dynamics and the Bicoid gradient using laminar flows of different temperature in a microfluidic device to determine if stability of the Bicoid gradient prior to cellularization is essential for precise patterning. Dramatic motion of both cytoplasm and nuclei was observed prior to cellularization, and the Bicoid gradient was disrupted by nuclear motion and was highly abnormal as a function of egg length. Despite an abnormal Bicoid gradient during cycles 11–13, Even-skipped patterning in these embryos remained precise. These results indicate that the stability of the Bicoid gradient as a function of egg length is nonessential during syncytial blastoderm stages. Further, presumably no gradient formed by simple diffusion on the scale of egg length could be responsible for the robust antero-posterior patterning observed, as severe cytoplasmic and nuclear motion would disrupt such a gradient. Additional mechanisms for how the embryo could sense its dimensions and interpret the Bicoid gradient are discussed.
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DOI：
10.1073/pnas.0601378104
发表时间：
2007-01-23
影响因子：
11.1
作者：
Hong, Christian I.;Conrad, Emery D.;Tyson, John J.
通讯作者：
Tyson, John J.
DOI：
10.1083/jcb.122.1.113
发表时间：
1993-07
期刊：
The Journal of cell biology
影响因子：
--
作者：
Baker J;Theurkauf WE;Schubiger G
通讯作者：
Schubiger G
影响因子：
11.4
作者：
FRASCH, M;HOEY, T;LEVINE, M
通讯作者：
LEVINE, M
影响因子：
4.6
作者：
DeLotto, Robert;DeLotto, Yvonne;Lippincott-Schwartz, Jennifer
通讯作者：
Lippincott-Schwartz, Jennifer
影响因子：
64.5
作者：
DRIEVER, W;NUSSLEINVOLHARD, C
通讯作者：
NUSSLEINVOLHARD, C