Guo M, Davis D, Birchler J A
Division of Biological Sciences, University of Missouri, Columbia 65211, USA.
Genetics. 1996 Apr;142(4):1349-55. doi: 10.1093/genetics/142.4.1349.
Previous studies on gene expression in aneuploids revealed numerous trans-acting dosage effects. Segmental aneuploidy of each varied chromosomal region exhibited predominantly inverse effects on several target genes. Here, dosage regulation was examined in a maize (Zea mays L.) ploidy series where the complete genomic complement is varied. Total RNA from leaf tissue of monoploid, diploid, triploid, and tetraploid plants (1x, 2x, 3x, and 4x, respectively) was analyzed for the expression of 18 genes. For most tested genes, the transcript level per cell is directly proportional to structural gene dosage; that is, on a per genome basis, there is approximately equal expression among the four ploidies. Exceptional cases show a negative correlation of expression with ploidy or a positive correlation greater than expected from the structural gene dosage. These studies suggest that, in general, as structural gene dosage increases in multiples of the monoploid complement, the absolute level of gene expression per cell increases. In contrast, addition or subtraction of only a single chromosome arm tends to alter gene expression patterns extensively. The combined results of the euploid and aneuploid studies suggest that aneuploid effects result from an altered stoichiometry of the factors contributing to the mechanisms of gene expression.
先前对非整倍体基因表达的研究揭示了众多反式作用剂量效应。每个不同染色体区域的片段非整倍体对几个靶基因主要表现出相反的效应。在此，在一个基因组完整互补倍数不同的玉米（Zea mays L.）倍性系列中研究了剂量调控。分析了单倍体、二倍体、三倍体和四倍体植株（分别为1x、2x、3x和4x）叶片组织的总RNA中18个基因的表达情况。对于大多数测试基因，每个细胞的转录水平与结构基因剂量成正比；也就是说，在每个基因组的基础上，这四个倍性之间的表达大致相等。特殊情况表现为表达与倍性呈负相关或呈正相关，且大于结构基因剂量预期的正相关。这些研究表明，一般来说，随着单倍体互补倍数的增加，结构基因剂量增加，每个细胞的基因表达绝对水平也会增加。相比之下，仅增加或减少一条染色体臂往往会广泛改变基因表达模式。整倍体和非整倍体研究的综合结果表明，非整倍体效应是由参与基因表达机制的因子化学计量改变所致。
