Yu J J, Smithson S L, Thomas P W, Kirkland T N, Cole G T
Department of Microbiology and Immunology, Medical College of Ohio, Toledo 43699, USA.
Gene. 1997 Oct 1;198(1-2):387-91. doi: 10.1016/s0378-1119(97)00342-9.
The urease (URE)-encoding gene from Coccidioides immitis (Ci), a respiratory fungal pathogen of humans, was cloned, sequenced, chromosome-mapped and expressed. Both the genomic and cDNA sequences are reported. The transcription start point and poly(A)-addition site were confirmed. The URE gene contains eight introns and a 2517-bp ORF that translates a 839-amino-acid (aa) protein of 91.5 kDa and pI of 5.5, as deduced by computer analysis of the nucleotide sequence. The translated protein revealed eight putative N-glycosylation sites. The deduced URE showed comparable levels of homology to reported URE of the jack bean plant (Canavalia ensiformis; 71.8%) and URE of several genera of bacteria (Bp, 71.7%; Hp, 68.3%; Ka, 71.6%; Pm, 71.9%). The URE gene was mapped to chromosome III of Ci and was shown to be a single copy gene by Southern hybridization. Expression of a 1687-bp fragment of the URE gene in E. coli resulted in the production of a 63-kDa recombinant protein that was recognized in an immunoblot by antiserum raised against the Ka URE homolog. This is the first report of a fungal URE gene.
从人类呼吸道真菌病原体粗球孢子菌（Ci）中克隆、测序、进行染色体定位并表达了脲酶（URE）编码基因。报告了基因组序列和cDNA序列。确定了转录起始点和聚腺苷酸化位点。URE基因包含8个内含子和一个2517 bp的开放阅读框（ORF），通过对核苷酸序列的计算机分析推断，该开放阅读框可翻译出一个91.5 kDa、pI为5.5的839个氨基酸（aa）的蛋白质。翻译后的蛋白质显示有8个推定的N-糖基化位点。推导的URE与刀豆植物（Canavalia ensiformis）报道的URE（71.8%）以及几种细菌属的URE（Bp，71.7%；Hp，68.3%；Ka，71.6%；Pm，71.9%）具有相当水平的同源性。URE基因被定位到Ci的第三条染色体上，通过Southern杂交显示为单拷贝基因。URE基因的一个1687 bp片段在大肠杆菌中表达，产生了一种63 kDa的重组蛋白，该蛋白在免疫印迹中被针对Ka URE同源物产生的抗血清所识别。这是关于真菌URE基因的首次报道。
