Arkhipova I, Li J, Meselson M
Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
Genetics. 1997 Mar;145(3):729-36. doi: 10.1093/genetics/145.3.729.
A procedure is described for determining the mode and magnitude of gene-dosage compensation of transformed genes. It involves measurement of the ratio of the activity of a gene inserted at X-linked sites to the activity of the same gene inserted at autosomal sites. Applying the procedure to the Drosophila pseudoobscura Hsp82 gene inserted at ectopic sites in D. melanogaster and taking gene activity as proportional to the amount of transcript per gene copy, we conclude that (1) in both adults and larvae the gene is not compensated at autosomal sites or at a site in beta-heterochromatin at the base of the X chromosome and is fully compensated at euchromatic X-chromosomal sites; (2) inappropriate normalization is responsible for a claim that the gene is compensated at autosomal sites; and (3) the observed compensation operates mainly or entirely by heightened activity of X-linked genes in males, rather than by reduced activity in females.
本文描述了一种确定转化基因的基因剂量补偿模式和幅度的方法。该方法包括测量插入X连锁位点的基因活性与插入常染色体位点的同一基因活性的比值。将该方法应用于插入黑腹果蝇异位位点的拟暗果蝇Hsp82基因，并将基因活性视为与每个基因拷贝的转录本数量成正比，我们得出以下结论：(1) 在成虫和幼虫中，该基因在常染色体位点或X染色体基部的β异染色质位点均未得到补偿，而在常染色质X染色体位点得到了完全补偿；(2) 不恰当的标准化导致了该基因在常染色体位点得到补偿的说法；(3) 观察到的补偿主要或完全是通过雄性中X连锁基因活性的增强，而不是雌性中活性的降低来实现的。
