Rogers M J, Steinmetz A A, Walker R T
Institut de Biologie Moleculaire et Cellulaire du CNRS, Strasbourg, France.
Isr J Med Sci. 1987 May;23(5):357-60.
To investigate the organization of tRNA genes in the honeybee pathogen, Spiroplasma melliferum (previously referred to as Spiroplasma sp. BC3), total labeled tRNA from S. melliferum was used as a hybridization probe to an EcoRI digest of the genomic DNA. The results show two, or possibly three, strongly hybridizing bands. Comparing the pattern obtained to that of Bacillus subtilis DNA suggests either that the S. melliferum tRNA genes are more extensively clustered or, more likely, that the S. melliferum genome does not encode a full complement of tRNA genes, as has been suggested for other Mollicutes. We screened a library of EcoRI fragments of S. melliferum DNA cloned in pBR322 with total radioactive tRNA as a probe and selected one of the tRNA gene clusters. Subsequent sequence analysis of a portion of the clone showed 10 tRNA genes probably comprising a single operon. Comparison of sequence with a tRNA gene cluster from Mycoplasma mycoides and a portion of a cluster from B. subtilis showed an identical order of tRNA genes and the isoacceptors encoded. Such a striking comparison in gram-positive eubacteria suggests an important function for regulation and co-transcription of these tRNA genes.
为了研究蜜蜂病原体蜜蜂螺原体（以前称为螺原体属BC3）中tRNA基因的组织情况，将来自蜜蜂螺原体的总标记tRNA用作基因组DNA的EcoRI酶切片段的杂交探针。结果显示有两条，也可能是三条强杂交带。将所得图谱与枯草芽孢杆菌DNA的图谱进行比较表明，要么蜜蜂螺原体的tRNA基因聚类更为广泛，要么更有可能的是，正如对其他柔膜菌纲所提出的那样，蜜蜂螺原体基因组并未编码完整的tRNA基因互补序列。我们用总放射性tRNA作为探针，筛选了克隆于pBR322中的蜜蜂螺原体DNA的EcoRI片段文库，并选择了其中一个tRNA基因簇。对该克隆的一部分进行后续序列分析显示，可能包含单个操纵子的10个tRNA基因。将该序列与来自丝状支原体的一个tRNA基因簇以及枯草芽孢杆菌的一个簇的一部分进行比较，结果显示tRNA基因及其编码的同功受体具有相同的顺序。在革兰氏阳性真细菌中如此显著的比较表明这些tRNA基因在调控和共转录方面具有重要功能。
