Satellite 2 DNA is a tandemly repeated, 330 bp sequence that is evolutionarily conserved among species belonging to the amphibian order, Caudata. Previous studies have shown that synthetic satellite 2 transcripts from the newt, Notophthalmus viridescens, self-cleave in vitro via a small structural motif called the hammerhead domain. Here we show that multimeric satellite 2 transcripts in the non-ovarian tissues of the newt self-cleave to generate monomeric satellite 2 transcripts. In contrast, monomeric transcripts in the newt ovary have $5\sp\prime$ and $3\sp\prime$ ends that are permuted 42 nucleotides upstream relative to the site of self-cleavage, and the $5\sp\prime$ ends of ovarian monomers are produced directly by transcription initiation rather than by self-cleavage. / By injecting cloned satellite 2 DNA into Xenopus oocytes, we determined that the satellite promoter is both structurally and functionally related to the small nuclear RNA (snRNA) gene promoters. Further comparison of satellite 2 DNA to the snRNA genes revealed that conserved core of the self-cleaving hammerhead domain resemble Boxes C and D found in several snRNAs. In addition, synthetic satellite 2 transcripts injected into Xenopus oocytes are immunoprecipitable by the anti-trimethylguanosine antibody, and endogenous nuclear satellite 2 transcripts in the newt oocyte possess the trimethylguanosine cap structure. / These data suggest that satellite 2 DNA is a member of the snRNA gene family. Accordingly, satellite 2 homologues are expected to exist in other vertebrate species. However, an extensive search in the genomes of non-Caudate amphibians such as Xenopus laevis has failed to detect the satellite 2 homologue. Based on our results, we propose that satellite 2 represents a Caudate-specific pseudogene family derived from an unidentified true snRNA gene. Apparently, significant sequence divergence between satellite 2 DNA and the putative progenitor gene have precluded the detection of the progenitor gene by standard hybridization methodologies using satellite 2 probes. / Source: Dissertation Abstracts International, Volume: 56-07, Section: B, page: 3591. / 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_77502 |
| Contributors | Coats, Stephen Reddell., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 145 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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