Orozco E M, Rushlow K E, Dodd J R, Hallick R B
J Biol Chem. 1980 Nov 25;255(22):10997-1003.
The DNA sequences of two segments of the ribosomal RNA transcription units of Euglena gracilis Pringsheim strain Z chloroplast DNA have been determined. The first is from the 16 S to 23 S rRNA spacer region. The nucleotide sequence determined includes 64 bp from the 3'-end of the 16 S rRNA gene, the adjacent 87-bp spacer containing 68A-T base pairs, a tRNAIle gene, a 9-bp spacer, a tRNAAla gene, a spacer of approximately 15 bp, and the first 120 bp from the 5'-end of the 23 S rRNA gene. The gene organization of the 16 S to 23 S rRNA spacer, the identity of the tRNA genes, and the tRNA anticodons for the E. gracilis rRNA transcription units are identical with that of the rrnA, D, and X operons of Escherichia coli. The second DNA segment which was sequenced is from a region preceding the 5'-end of the 16 S rRNA gene. Within a continuous region of 189 bp in this 16 S rRNA leader sequence, 68% of the bases are homologous to the 16 S rRNA to 23 S rRNA spacer region. This homology includes the 3'-end of the 16 S rRNA gene, the adjacent spacer, and a complete "pseudo" tRNAIle gene. This leader sequence which has the same polarity as the rRNA transcripts, is flanked by nucleotide sequences resembling partial tRNA genes.
已经测定了纤细裸藻普林斯海姆品系Z叶绿体DNA核糖体RNA转录单元两个片段的DNA序列。第一个片段来自16S至23S rRNA间隔区。所测定的核苷酸序列包括16S rRNA基因3'端的64个碱基对、相邻的含68个A-T碱基对的87个碱基对的间隔区、一个异亮氨酸tRNA基因、一个9个碱基对的间隔区、一个丙氨酸tRNA基因、一个约15个碱基对的间隔区以及23S rRNA基因5'端的前120个碱基对。纤细裸藻rRNA转录单元16S至23S rRNA间隔区的基因组织、tRNA基因的同一性以及tRNA反密码子与大肠杆菌的rrnA、D和X操纵子相同。测序的第二个DNA片段来自16S rRNA基因5'端之前的区域。在这个16S rRNA前导序列189个碱基对的连续区域内，68%的碱基与16S rRNA至23S rRNA间隔区同源。这种同源性包括16S rRNA基因的3'端、相邻的间隔区以及一个完整的“假”异亮氨酸tRNA基因。这个与rRNA转录本具有相同极性的前导序列两侧是类似于部分tRNA基因的核苷酸序列。
