The three-dimensional organization of polytene nuclei in male Drosophila melanogaster with compound XY or ring X chromosomes.
The three-dimensional organization of polytene nuclei in male Drosophila melanogaster with compound XY or ring X chromosomes.
复制标题
具有复合 XY 或环 X 染色体的雄性黑腹果蝇多线核的三维组织。
DOI：
10.1093/genetics/121.2.293
复制
发表时间：
1989
期刊：
影响因子：
3.3
通讯作者：
Sedat,JW
中科院分区：
文献类型：
--
作者：
Mathog,D;Sedat,JW
研究了雄性果蝇（Drosophilamelanogaster）多线染色体在含有重排X染色体的核内的三维结构。将含有倒置X染色体（YSX.YL，In（1）EN/O）或环状X染色体（R（1）2/BSYy+）的三龄幼虫唾液腺固定、包埋并连续切片。对相邻细胞组中的细胞核进行建模和分析。我们发现，对于这两种基因型的三维行为在每个常染色质基因座是独立的染色体上，它驻留的方向，独立的行为的基因座不紧密相连，并在相邻的细胞不相似。在以前的研究中注意到的右手染色体卷曲的偏好被证明是独立的同源配对。然而，只有在同源配对的染色体中，染色体弯曲的程度和染色体卷曲的手性之间才存在关系。附加的XY染色体有两个以前未描述的行为：近端异染色质/常染色质交界处的常染色质侧与核仁的几乎不变的关联，以及该位点经常无法附着到染色中心。染色体臂的相对位置在几个相邻细胞中通常是相似的。假设这些细胞块代表克隆，它们的大小表明这种排列最多是准稳定的：它们可以维持至少一次，但少于四次细胞分裂。在唾液腺中观察到的核组织与多线核中的位置在常染色质基因座的正常遗传调节中起主要作用的观点不一致。
The three-dimensional organization of polytene chromosomes within nuclei containing rearranged X chromosomes was examined in male Drosophila melanogaster. Salivary glands of third instar larvae containing either an inverted X chromosome (YSX.YL, In(1)EN/O) or a ring X chromosome (R(1) 2/BSYy+) were fixed, embedded, and serially sectioned. The nuclei in contiguous groups of cells were modeled and analyzed. We find that for both genotypes the three-dimensional behavior at each euchromatic locus is independent of the orientation of the chromosome on which it resides, independent of the behavior of loci not closely linked to it, and not similar in neighboring cells. The preference for right-handed chromosome coiling noted in previous studies is shown to be independent of homologous pairing. However, a relation between the extent of chromosome curvature and the handedness of chromosome coiling is present only in homologously paired chromosomes. The attached-XY chromosome has two previously undescribed behaviors: a nearly invariant association of the euchromatic side of the proximal heterochromatin/euchromatin junction with the nucleolus and a frequent failure of this site to attach to the chromocenter. The relative chromosome arm positions are often similar in several neighboring cells. The size of these patches of cells, assuming that they represent clones, indicates that such arrangements are at best quasi-stable: they may be maintained over at least one, but less than four, cell divisions. The observed nuclear organization in salivary glands is inconsistent with the idea that position in the polytene nucleus plays a major role in the normal genetic regulation of euchromatic loci.