Expression Studies on Clustered Trypanosomatid Box C/D Small Nucleolar RNAs
We analyzed three chromosomal loci of the trypanosomatid Leptomonas collosoma encoding box C/D small nucleolar RNAs (snoRNAs). All the snoRNAs that were analyzed here carry two sequences complementary to rRNA target sites and obey the +5 rule for guide methylation. Studies on transgenic parasites carrying the snoRNA-2 gene in the episomal expression vector (pX-neo) indicated that no promoter activity was found immediately adjacent to this gene. Deleting the flanking sequences of snoRNA-2 affected the expression; in the absence of the 3′-flanking (but not 5′-flanking) sequence, the expression was almost completely abolished. The snoRNA genes are transcribed as polycistronic RNA. All snoRNAs can be folded into a common stem-loop structure, which may play a role in processing the polycistronic transcript, snoRNA B2, a member of a snoRNA cluster, was expressed when cloned into the episomal vector, suggesting that each gene within a cluster is individually processed. Studies with permeable cells indicated that snoRNA gene transcription was relatively sensitive to α-amanitin, thus supporting transcription by RNA polymerase II. We propose that snoRNA gene expression, similar to protein-coding genes in this family, is regulated at the processing level.
Journal of Biological Chemistry
Xu, Y., Liu, L., Lopez-Estraño, C., & Michaeli, S. (2001). Expression Studies on Clustered Trypanosomatid Box C/D Small Nucleolar RNAs. Journal of Biological Chemistry, 276 (17), 14289-14298. https://doi.org/10.1074/jbc.M007007200