Shirley B W, Goodman H M
Department of Genetics, Harvard Medical School, Boston, MA 02114.
Mol Gen Genet. 1993 Dec;241(5-6):586-94. doi: 10.1007/BF00279901.
A gene encoding a protein with extensive homology to the largest subunit of the multicatalytic proteinase complex (proteasome) has been identified in Arabidopsis thaliana. This gene, referred to as AtPSM30, is entirely encompassed within a previously characterized radiation-induced deletion, which may thus provide the first example of a proteasome null mutation in a higher eukaryote. However, the growth rate and fertility of Arabidopsis plants do not appear to be significantly affected by this mutation, even though disruption experiments in yeast have shown that most proteasome subunits are essential. Analysis of mRNA levels in developing seedlings and mature plants indicates that expression of AtPSM30 is differentially regulated during development and is slightly induced in response to stress, as has been observed for proteasome genes in yeast, Drosophila, and mammals. Southern blot analysis indicates that the Arabidopsis genome contains numerous sequences closely related to AtPSM30, consistent with recent reports of at least two other proteasome genes in Arabidopsis. A comparison of the deduced amino acid sequences for all proteasome genes reported to date suggests that multiple proteasome subunits evolved in eukaryotes prior to the divergence of plants and animals.
在拟南芥中已鉴定出一个与多催化蛋白酶复合体（蛋白酶体）最大亚基具有广泛同源性的蛋白质编码基因。这个基因被称为AtPSM30，它完全包含在先前已表征的辐射诱导缺失区域内，因此这可能是高等真核生物中蛋白酶体无效突变的首个实例。然而，尽管酵母中的破坏实验表明大多数蛋白酶体亚基是必不可少的，但拟南芥植株的生长速率和育性似乎并未受到该突变的显著影响。对发育中的幼苗和成熟植株中mRNA水平的分析表明，AtPSM30的表达在发育过程中受到差异调节，并且在应激反应中略有诱导，这与酵母、果蝇和哺乳动物中蛋白酶体基因的情况一致。Southern杂交分析表明，拟南芥基因组包含许多与AtPSM30密切相关的序列，这与最近关于拟南芥中至少另外两个蛋白酶体基因的报道一致。对迄今报道的所有蛋白酶体基因推导的氨基酸序列进行比较表明，在动植物分化之前，真核生物中就已进化出多个蛋白酶体亚基。
