Hood Heather M, Spevak Christina C, Sachs Matthew S
Department of Environmental and Biomolecular Systems, Oregon Health & Science University, Beaverton, OR 97006-8921, USA.
Fungal Genet Biol. 2007 Feb;44(2):93-104. doi: 10.1016/j.fgb.2006.07.009. Epub 2006 Sep 18.
The Neurospora crassa arg-2 and the Saccharomyces cerevisiae ortholog CPA1 encode the arginine-specific carbamoyl-phosphate synthetase (CPS-A) small subunit. Arginine decreases synthesis of this subunit through the action of a 5' upstream open reading frame in the mRNA that encodes a cis-regulatory element, the arginine attenuator peptide (AAP), which stalls ribosomes in response to arginine. We performed a comparative analysis of the genomic structure and predicted peptide sequence of the AAP and CPS-A small subunit across many fungi. Differences at the genomic level included variation in intron number and position within the AAP and CPS-A coding regions and differences in known regulatory motifs. Although differences exist in AAP sequence, there were three absolutely conserved amino acid residues in the predicted peptide, including an aspartic acid crucial for arginine-dependent regulation of arg-2 and CPA1. A diverged Basidiomycete AAP was shown to retain function as an Arg-specific negative regulator of translation.
粗糙脉孢菌的arg-2和酿酒酵母的直系同源基因CPA1编码精氨酸特异性氨甲酰磷酸合成酶（CPS-A）小亚基。精氨酸通过mRNA中5'上游开放阅读框的作用减少该亚基的合成，该开放阅读框编码一个顺式调控元件，即精氨酸衰减肽（AAP），它会响应精氨酸使核糖体停滞。我们对多种真菌中AAP和CPS-A小亚基的基因组结构和预测的肽序列进行了比较分析。基因组水平的差异包括AAP和CPS-A编码区域内内含子数量和位置的变化以及已知调控基序的差异。尽管AAP序列存在差异，但预测的肽中有三个绝对保守的氨基酸残基，包括一个对arg-2和CPA1的精氨酸依赖性调控至关重要的天冬氨酸。一种分化的担子菌AAP被证明保留了作为精氨酸特异性翻译负调控因子的功能。
