Satellite 2 is a 300-350 bp tandemly repeated DNA that is highly conserved in different salamander families. While the function of satellite 2 is not known, it has the ability to promote transcription using a self-contained snRNA type of promoter and its transcripts can catalyze their own site-specific cleavage using an extended hammerhead domain. An analysis of chimeric hammerheads indicated that the different stem I extensions were active only in the context of compatible stem II regions. To investigate this compatibility requirement, partial satellite 2 sequences containing the extended hammerhead domain were cloned and characterized from six species representing four Caudate families. Results indicated that satellite 2 elements exist in every Caudate family except Sirenidae. Despite differences in the abundance of this element and its transcripts, the tandemly repeated genomic organization and the tissue specific transcript patterns have been conserved. Comparison of the satellite 2 sequences from different species suggested the existence of at least two groups, and they might evolve at different rates in different families. Sequence analysis also revealed that the species consensus sequence is under selection while individual repeats are free to diverge. However, this selection is not for increasing the cleavage ability of its extended hammerhead. Although each species consensus sequence can form an extended hammerhead that has the same central core and the same secondary structure, these extended hammerheads have very different in vitro cleavage rates. Since the differences are primarily in the stem I and stem II regions, the results suggest that both regions are important for self-cleavage. / Source: Dissertation Abstracts International, Volume: 56-07, Section: B, page: 3611. / Major Professor: Lloyd M. Epstein. / Thesis (Ph.D.)--The Florida State University, 1995.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_77510 |
| Contributors | Zhang, Yi., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 105 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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