Dietrich P, Soares M B, Affonso M H, Floeter-Winter L M
Departmento de Parasitologia, Universidade de São Paulo, Brazil.
Gene. 1993 Mar 15;125(1):103-7. doi: 10.1016/0378-1119(93)90753-p.
The transcription start point (tsp) of the ribosomal RNA(rRNA)-encoding gene of Trypanosoma cruzi was mapped at 1550 bp upstream from the 18S rRNA coding sequence. The + 1 nucleotide (tsp) was determined to be a guanosine. As described for other eukaryotes, no consensus sequence was found when the putative promoter sequence (-200 to + 50) was compared with that described for Trypanosoma brucei and Crithidia fasciculata. However, a repeated element was found in the upstream intergenic spacer sequence (IGS) of T. cruzi. Motifs, present in this element, exhibit significant homology to the T. cruzi promoter sequence. Furthermore, the same motifs could be found, in a similar sequence organization, within the T. brucei promoter region. Therefore, the data described in this paper strongly indicate that the IGS rDNA (DNA coding for rRNA) organization in trypanosomatids appears similar to that found in higher eukaryotes.
克氏锥虫核糖体RNA（rRNA）编码基因的转录起始点（tsp）被定位在18S rRNA编码序列上游1550 bp处。确定 +1核苷酸（tsp）为鸟苷。正如对其他真核生物所描述的那样，当将推定的启动子序列（-200至 +50）与布氏锥虫和fasiculata短膜虫所描述的序列进行比较时，未发现共有序列。然而，在克氏锥虫的上游基因间隔序列（IGS）中发现了一个重复元件。该元件中存在的基序与克氏锥虫启动子序列具有显著同源性。此外，在布氏锥虫启动子区域内，可以发现相同的基序，其序列组织相似。因此，本文所述数据强烈表明，锥虫的IGS rDNA（编码rRNA的DNA）组织似乎与高等真核生物中的相似。
