Abundant, diverse, and consequential P elements segregate in promoters of small heat-shock genes in Drosophila populations
Abundant, diverse, and consequential P elements segregate in promoters of small heat-shock genes in Drosophila populations
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DOI：
10.1111/j.1420-9101.2007.01348.x
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发表时间：
2007-09-01
影响因子：
2.1
通讯作者：
Feder, M. E.
中科院分区：
文献类型：
--
作者：
Chen, B.;Walser, J.-C.;Feder, M. E.
本研究通过检测两个小热休克基因近端启动子区域自然发生的P元素插入的基因型多样性和表型后果，进一步证明果蝇热休克基因由于转座元件的插入而具有独特的可进化性。对两个种群的详细观察显示，16个独特的P转座元件共同分离在两个小热休克基因Hsp26和Hsp27的近端启动子中。这些元素的大小、方向和插入位置各不相同。在这些人群中，含P元素等位基因的频率从5%到100%不等。详细研究选择的两个Hsp26元件R(s)P（26）和D(2)P(m)分别降低或消除Hsp26的表达。R(s)P（26）元素增加或不影响高温诱导耐受性，提高了繁殖力，但降低了发育速率。另一方面，D(2)P(m)元素降低了耐热性和繁殖力。在经过实验进化的品系中，R(s)P(26)P元素的等位基因频率变化很大，并且在为延长寿命和加速发育而选择的品系中，其频率低于对照。在果蝇种群中，转座因子插入小热休克蛋白基因可以产生显著的适应性结果，因此产生了选择可以起作用的变异。
The present study extends evidence that Drosophila heat-shock genes are distinctively evolvable because of insertion of transposable elements by examining the genotypic diversity and phenotypic consequences of naturally occurring P element insertions in the proximal promoter regions of two small heat-shock genes. Detailed scrutiny of two populations revealed 16 distinctive P transposable elements collectively segregating in proximal promoters of two small heat-shock genes, Hsp26 and Hsp27. These elements vary in size, orientation and insertion site. Frequencies of P element-containing alleles varied from 5% to 100% in these populations. Two Hsp26 elements chosen for detailed study, R(s)P(26) and D(2)P(m), reduced or abolished Hsp26 expression respectively. The R(s)P(26) element increased or did not affect inducible tolerance of high temperature, increased fecundity, but decreased developmental rate. On the other hand, the D(2)P(m) element decreased thermotolerance and fecundity. In lines subjected to experimental evolution, the allelic frequency of the R(s)P(26)P element varied considerably, and was at lower frequencies in lines selected for increased longevity and for accelerated development than in controls. Transposable element insertions into small Hsp genes in Drosophila populations can have dramatic fitness consequences, and therefore create variation on which selection can act.