The role of Bicoid cooperative binding in the patterning of sharp borders in Drosophila melanogaster.
The role of Bicoid cooperative binding in the patterning of sharp borders in Drosophila melanogaster.
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Bicoid 合作结合在果蝇尖锐边界图案化中的作用。
DOI：
10.1016/j.ydbio.2012.07.020
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发表时间：
2012
影响因子：
2.7
通讯作者：
Bisch,PauloM
中科院分区：
文献类型：
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作者：
Lopes,FranciscoJP;Spirov,AlexanderV;Bisch,PauloM
在果蝇胚胎发育中，Bicoid（Bcd）蛋白建立了下游发育基因的位置信息，如hunchback（hb），其在胚胎中期具有强烈的前部表达和尖锐的开关边界。Bcd协同结合在Hb模式定位中的作用已在先前得到证实。然而，有报道的结果中的差异，这一机制的作用，在尖锐的血红蛋白边界。在这里，我们确定了Bcd在野生型（WT）胚胎中产生Hb尖锐边界所需的希尔系数（nH）。我们发现，约6.3（s.d.）1.4)和10.8（s.d.）4.0)需要分别考虑在早期和晚期周期14A的Hb锐度。可能需要其他机制，因为Bcd与hb启动子结合可能无法获得高nHis。为了验证这一观点，我们测定了15个表达自身激活缺陷的hb14F等位基因的胚胎的Hb图谱所需的nH，发现nH为3.0（s.d.）。1.0）。这一结果表明，在WT胚胎中，血红蛋白自激活对于血红蛋白的清晰度很重要。证实我们的研究结果，我们还发现了一个逐步增加所需的值nHspanning从4.0到9.2，通过确定这个系数从平均配置文件的8个时间类在周期14A（T1至T8）。我们的研究结果表明，有一个过渡的机制，负责尖锐的Hb边界在周期14 A：在这个周期的早期阶段，Bcd合作结合主要负责Hb的锐度，在周期14 A后期，Hb自激活成为主导机制。
In Drosophila embryonic development, the Bicoid (Bcd) protein establishes positional information of downstream developmental genes like hunchback (hb), which has a strong anterior expression and a sharp on-off boundary in the mid-embryo. The role of Bcd cooperative binding in the positioning of the Hb pattern has been previously demonstrated. However, there are discrepancies in the reported results about the role of this mechanism in the sharp Hb border. Here, we determined the Hill coefficient (nH) required for Bcd to generate the sharp border of Hb in wild-type (WT) embryos. We found that an nHof approximately 6.3 (s.d. 1.4) and 10.8 (s.d. 4.0) is required to account for Hb sharpness at early and late cycle 14A, respectively. Additional mechanisms are possibly required because the high nHis likely unachievable for Bcd binding to the hb promoter. To test this idea, we determined the nHrequired to pattern the Hb profile of 15 embryos expressing an hb14Fallele that is defective in self-activation and found nHto be 3.0 (s.d. 1.0). This result indicates that in WT embryos, the hb self-activation is important for Hb sharpness. Corroborating our results, we also found a progressive increase in the required value of nHspanning from 4.0 to 9.2 by determining this coefficient from averaged profiles of eight temporal classes at cycle 14A (T1 to T8). Our results indicate that there is a transition in the mechanisms responsible for the sharp Hb border during cycle 14A: in early stages of this cycle, Bcd cooperative binding is primarily responsible for Hb sharpness; in late cycle 14A, hb self-activation becomes the dominant mechanism.