Devlin R H, Holm D G, Grigliatti T A
Department of Zoology, University of British Columbia, Vancouver, Canada.
Genetics. 1988 Jan;118(1):87-101. doi: 10.1093/genetics/118.1.87.
The biochemical consequences of extensive aneuploidy in Drosophila have been examined by measuring the levels of specific proteins in larvae trisomic for entire chromosome arms. By far the most common effect is a reduction in gene product levels (per gene template) by one-third from the diploid quantity, consistent with the model that concentration-dependent repressors of these loci reside on the duplicated chromosome arms. Most loci appear sensitive to such repression in one or more of the trisomies examined, suggesting that such regulatory loci might be quite common. Repression of gene-product levels in trisomies may significantly contribute to their inviability. Few loci are activated in trisomies implying that most factors necessary for gene expression are in excess. While autosomal trisomies can repress the expression of both X-linked and autosomal loci, X-chromosomal trisomies have little effect on most autosomal genes. A family of genes coding for larval serum proteins do not respond similarly in trisomies, suggesting that regulation operates on a process which is not common to their coordinate regulation. Finally, Adh genes transposed to new chromosomal positions maintain their ability to be repressed in 3L trisomies suggesting that this response to regulation involves a closely linked cis-acting regulatory element.
通过测量整条染色体臂三体的果蝇幼虫中特定蛋白质的水平，研究了广泛非整倍性的生化后果。到目前为止，最常见的效应是基因产物水平（每个基因模板）比二倍体数量减少三分之一，这与这些基因座的浓度依赖性阻遏物位于重复的染色体臂上的模型一致。在所检测的一个或多个三体中，大多数基因座似乎对这种阻遏敏感，这表明此类调控基因座可能相当常见。三体中基因产物水平的阻遏可能显著导致其无法存活。三体中很少有基因座被激活，这意味着基因表达所需的大多数因子都过量。虽然常染色体三体可以抑制X连锁基因座和常染色体基因座的表达，但X染色体三体对大多数常染色体基因几乎没有影响。一组编码幼虫血清蛋白的基因在三体中的反应并不相似，这表明调控作用于一个与其协同调控不共有的过程。最后，转座到新染色体位置的乙醇脱氢酶（Adh）基因在3L三体中仍保持其被阻遏的能力，这表明这种对调控的反应涉及一个紧密连锁的顺式作用调控元件。
