LOCALIZATION OF P-ELEMENTS, COPY NUMBER REGULATION, AND CYTOTYPE DETERMINATION IN DROSOPHILA-MELANOGASTER
LOCALIZATION OF P-ELEMENTS, COPY NUMBER REGULATION, AND CYTOTYPE DETERMINATION IN DROSOPHILA-MELANOGASTER
复制标题
DOI：
10.1017/s0016672300028822
复制
发表时间：
1990-08-01
影响因子：
1.5
通讯作者：
GAUTIER, C
中科院分区：
文献类型：
--
作者：
BIEMONT, C;RONSSERAY, S;GAUTIER, C
对从M‘’品系(杂种不育的P/M系)中提取的17个高自交系黑腹果蝇进行了细胞型、完全P元件和缺陷P元件的数目和染色体定位的研究。虽然大多数品系是M细胞型，但有3个品系表现为P细胞型(抑制P元件活性的状态)，1个品系介于M和P之间。所有品系都具有KP元件，只有8个品系具有全尺寸的P元件。只有具有全尺寸P元件的品系在世代中表现出可检测到的P插入模式的变化；它们的P元件位点的增益率和丢失率分别等于每基因组每代0.12和0.09。在品系内，这两个比率之间没有相关性，这表明近交系基因组中存在独立的换位和切除。Southern印迹分析和从P元件左右两侧制备的探针的原位杂交结果都强烈地表明，在三个P细胞型的品系中，X染色体的1A区存在一个完整的P元件，而在M细胞型的品系中，这一区域没有P拷贝，这支持了这样的假设，即插入到1A中的P元件在P细胞型的确定中可能起主要作用。在13个M系中有9个在93F区还观察到有缺陷的2kb P元件的插入。在我们的品系中，P元件拷贝数的调节似乎与全长和缺陷P元件的比例无关。
Seventeen highly-inbred lines of Drosophila melanogaster extracted from an M'' strain (in the P/M system of hybrid dysgenesis) were studied for their cytotype and the number and chromosomal location of complete and defective P elements. While most lines were of M cytotype, three presented a P cytotype (the condition that represses P-element activity) and one was intermediate between M and P. All lines were found to possess KP elements and only eight to bear full-sized P elements. Only the lines with full-sized P elements showed detectable changes in their P-insertion pattern over generations; their rates of gain and of loss of P-element sites were equal to 0.12 and 0.09 per genome, per generation, respectively. There was no correlation between these two rates within lines, suggesting independent transpositions and excisions in the inbred genomes. The results of both Southern blot analysis and in situ hybridization of probes made from left and right sides of the P element strongly suggested the presence of a putative complete P element in region 1A of the X chromosome in the three lines with a P cytotype; the absence of P copy in this 1A region in lines with an M cytotype, favours the hypothesis that the P element inserted in 1A could play a major role in the P-cytotype determination. Insertion of a defective 2 kb P element was also observed in region 93F in 9 of the 13 M lines. The regulation of the P-element copy number in our lines appeared not to be associated with the ratio of full-length and defective P elements.