Department of the Chromosome Structure and Function, Laboratory of Molecular Cytogenetics, Institute of Molecular and Cellular Biology SB RAS, 630090 Novosibirsk, Russia.
Department of Systems Biology, Laboratory of Evolutionary Bioinformatics and Theoretical Genetics, Institute of Cytology and Genetics SB RAS, 630090 Novosibirsk, Russia.
Genes (Basel). 2020 Apr 11;11(4):417. doi: 10.3390/genes11040417.
The polytene chromosomes are the best model for studying the genome organization during interphase. Despite of the long-term studies available on genetic organization of polytene chromosome bands and interbands, little is known regarding long gene location on chromosomes. To analyze it, we used bioinformatic approaches and characterized genome-wide distribution of introns in gene bodies and in different chromatin states, and using fluorescent in situ hybridization we juxtaposed them with the chromosome structures. Short introns up to 2 kb in length are located in the bodies of housekeeping genes (grey bands or chromatin). In the group of 70 longest genes in the genome, 95% of total gene length accrues to introns. The mapping of the 15 long genes showed that they could occupy extended sections of polytene chromosomes containing band and interband series, with promoters located in the interband fragments ( chromatin). Introns ( and chromatin) in polytene chromosomes form independent bands, which can contain either both introns and exons or intron material only. Thus, a novel type of the gene arrangement in polytene chromosomes was discovered; peculiarities of such genetic organization are discussed.
多线染色体是研究间期基因组组织的最佳模型。尽管对多线染色体带和带间的遗传组织已有长期的研究，但对于染色体上的长基因位置却知之甚少。为了分析这一点，我们使用了生物信息学方法，描述了内含子在基因体和不同染色质状态中的全基因组分布，并使用荧光原位杂交将它们与染色体结构并列。长度在 2kb 以下的短内含子位于管家基因（灰色带或染色质）的基因体中。在基因组中 70 个最长基因的组中，总基因长度的 95%是内含子。对 15 个长基因的作图表明，它们可以占据多线染色体的扩展部分，这些部分包含带和带间系列，启动子位于带间片段（染色质）中。多线染色体中的内含子（和染色质）形成独立的带，这些带可以既包含内含子和外显子，也可以只包含内含子物质。因此，在多线染色体中发现了一种新的基因排列类型；讨论了这种遗传组织的特点。
