Ortiz D F, Rowland L J, Gregerson R G, Strommer J N
Department of Genetics, University of Georgia, Athens 30602.
Mol Gen Genet. 1988 Sep;214(1):135-41. doi: 10.1007/BF00340191.
Insertion of a Mu transposable element at the Shrunken 1 (Sh1) locus of maize has resulted in kernels with the typical collapsed appearance of sh mutants. Molecular analysis of the mutant gene has revealed the presence of a 1.4 kb insertion immediately upstream from the normal transcriptional start site. Mu insertion has brought about a series of changes in gene expression: the mRNA cap site has been shifted downstream so that it now lies inside the Mu element; transcription is reduced approximately sixfold, and the sh mRNA steady-state level is less than 4% of that found in the nonmutant. This disparity reflects a mutational defect in post-transcriptional regulation which is manifested as a decrease in Sh RNA abundance.
在玉米的皱缩1（Sh1）位点插入一个Mu转座元件，导致籽粒呈现出sh突变体典型的皱缩外观。对该突变基因的分子分析表明，在正常转录起始位点上游紧邻处存在一个1.4 kb的插入片段。Mu插入导致了基因表达的一系列变化：mRNA帽位点已向下游移动，以至于现在位于Mu元件内部；转录减少了约六倍，并且sh mRNA的稳态水平不到非突变体中的4%。这种差异反映了转录后调控中的突变缺陷，表现为Sh RNA丰度的降低。
