| dc.contributor.author | Greenwood, Spencer John. | en_US |
| dc.date.accessioned | 2014-10-21T12:36:02Z | |
| dc.date.available | 1994 | |
| dc.date.issued | 1994 | en_US |
| dc.identifier.other | AAINN98856 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55439 | |
| dc.description | In most eukaryotes, the cytoplasmic ribosome contains a high-molecular-weight, large subunit (LSU) rRNA component termed the "28S rRNA". However, in the protist Euglena gracilis, the 28S rRNA is replaced by 13 separate rRNA species that result from extensive post-transcriptional processing. In the present study, the characteristics of this novel processing pathway were explored by northern hybridization and transcript mapping analyses. The processing pathway indicates that the small subunit (SSU) rRNA and the various fragments of the LSU rRNA are processed from a large precursor RNA of $\sim$10.2 kilobases by way of a number of unique RNA intermediates. | en_US |
| dc.description | Ribosomal RNA genes (rDNA) are typically found in eukaryotes as tandem repeats integrated into the chromosome. However, in Euglena there are instead about 1000 copies/cell of an $\sim$11 kilobase pair extrachromosomal circle that contains a single rDNA transcription unit. Primer extension analysis within the intergenic spacer (IGS) revealed that transcription of the rDNA in Euglena proceeds multiple times around the extrachromosomal circle without re-initiation. The results from the investigation of rRNA transcription and processing in Euglena are discussed in relation to a model of "read-around transcription". | en_US |
| dc.description | Small nucleolar RNAs (snoRNAs) have been implicated in the processing of rRNA and recent evidence has shown a specific requirement for U3 snoRNA in mammalian and yeast systems. For this reason the U3 snoRNA of Euglena was isolated and characterized. The 180 nucleotide sequence contains all the recognized U3 conserved boxes present in other eukaryotes. A potential secondary structure was determined that resembles that proposed for non-vertebrates. The organization of multiple U3-hybridizing sequences present in the genome is discussed in relation to the multiple expressed copies of U3 snoRNA found in Euglena. Complementarities found between the U3 snoRNA and the pre-rRNA of Euglena suggest possible sites of interaction for U3 snoRNA in rRNA processing. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1994. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Biology, Molecular. | en_US |
| dc.title | Ribosomal RNA processing in Euglena gracilis. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
