Tan M, Heckmann K, Brünen-Nieweler C
Institut für Allgemeine Zoologie und Genetik, Universität Münster, Germany.
J Eukaryot Microbiol. 2001 Jan-Feb;48(1):80-7. doi: 10.1111/j.1550-7408.2001.tb00418.x.
We have isolated and characterized the micronuclear gene encoding the regulatory subunit of cAMP-dependent protein kinase of the ciliated protozoan Euplotes octocarinatus, as well as its macronuclear version and the corresponding cDNA. Analyses of the sequences revealed that the micronuclear gene contains one small 69-bp internal eliminated sequence (IES) that is removed during macronuclear development. The IES is located in the 5'-noncoding region of the micronuclear gene and is flanked by a pair of tetranucleotide 5'-TACA-3' direct repeats. The macronuclear DNA molecule carrying this gene is approximately 1400 bp long and is amplified to about 2000 copies per macronucleus. Sequence analysis suggests that the expression of this gene requires a +1 ribosomal frameshift. The deduced protein shares 31% identity with the cAMP-dependent protein kinase type I regulatory subunit of Homo sapiens, and 53% identity with the regulatory subunit R44 of one of the two cAMP-dependent protein kinases of Paramecium. In addition, it contains two highly conserved cAMP binding sites in the C-terminal domain. The putative autophosphorylation site ARTSV of the regulatory subunit of E. octocarinatus is similar to that of the regulatory subunit R44 of Paramecium but distinct from the consensus motif RRXSZ of other eukaryotic regulatory subunits of cAMP-dependent protein kinases.
我们已经分离并鉴定了编码纤毛原生动物八肋游仆虫（Euplotes octocarinatus）环磷酸腺苷（cAMP）依赖性蛋白激酶调节亚基的微核基因，以及其大核版本和相应的互补脱氧核糖核酸（cDNA）。序列分析表明，微核基因包含一个69碱基对的小内部消除序列（IES），该序列在大核发育过程中被去除。IES位于微核基因的5'非编码区，两侧是一对四核苷酸5'-TACA-3'直接重复序列。携带该基因的大核DNA分子长度约为1400碱基对，每个大核中扩增至约2000个拷贝。序列分析表明，该基因的表达需要+1核糖体移码。推导的蛋白质与智人（Homo sapiens）I型cAMP依赖性蛋白激酶调节亚基具有31%的同一性，与草履虫（Paramecium）两种cAMP依赖性蛋白激酶之一的调节亚基R44具有53%的同一性。此外，它在C末端结构域包含两个高度保守的cAMP结合位点。八肋游仆虫调节亚基的推定自磷酸化位点ARTSV与草履虫调节亚基R44的相似，但与其他真核cAMP依赖性蛋白激酶调节亚基的共有基序RRXSZ不同。
