Deak J C, Doerder F P
Department of Biology, Cleveland State University, OH 44115, USA.
Gene. 1995 Oct 16;164(1):163-6. doi: 10.1016/0378-1119(95)00446-d.
The temperature-regulated SerH1 gene coding for an immunodominant surface glycoprotein (i-Ag H1) of Tetrahymena thermophila has been sequenced. The gene is reproducibly rearranged during macronuclear development and steady state mRNA levels are present at < 36 degrees C. The deduced i-Ag H1 amino acid (aa) sequence is rich in Ser, Thr and Cys, and contains three periods each consisting of 85 aa punctuated by eight Cys with the general formula, CX6CX17CX2CX18CX2CX11CX2CX19 (where X = any aa). Such Cys periodicity is common to ciliate i-Ag. Codon usage in Tt, Paramecium primaurelia and P. tetraurelia i-Ag encoding genes is similar, with approx. 80% A+T in the 3' position which is in marked contrast to the approx. 54% 3' A+T in other ciliate genes.
编码嗜热四膜虫免疫显性表面糖蛋白（i-Ag H1）的温度调节型SerH1基因已被测序。该基因在大核发育过程中可重复重排，且在低于36摄氏度时存在稳态mRNA水平。推导的i-Ag H1氨基酸（aa）序列富含丝氨酸、苏氨酸和半胱氨酸，并包含三个由85个氨基酸组成的区段，区段由八个半胱氨酸隔开，通式为CX6CX17CX2CX18CX2CX11CX2CX19（其中X = 任何氨基酸）。这种半胱氨酸周期性在纤毛虫i-Ag中很常见。嗜热四膜虫、双小核草履虫和四膜虫i-Ag编码基因中的密码子使用情况相似，3' 位置的A+T约为80%，这与其他纤毛虫基因中约54%的3' A+T形成显著对比。
