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Comparative Genetic And Genomic Analysis Of The Novel Fusellovirus Sulfolobus Spindle-Shaped Virus 10, David Andrew Goodman

Dissertations and Theses

Viruses that infect thermophilic Archaea are unique in both their structure and genetic makeup. The lemon-shaped fuselloviruses - which infect members of the order Sulfolobales, growing optimally at 80º C and pH 3 - are some of the most ubiquitous and best studied viruses of the thermoacidophilic Archaea. They provide a malleable and useful genetic tool for probing into the functions of their host, as well as the host responses to infection. Nonetheless, much about these viruses remains to be learned to further understand their morphological, genetic, and life cycle characteristics.

In order to investigate these aspects of these …

Interplay Of Transcription Factor E And Spt4/5 During Transcription Initiation In Pyrococcus Furiosus, Kimberly Kay Sheffield

Dissertations and Theses

Transcription, the first step in gene expression, is a highly regulated process which relies on a multi-protein complex to occur. Among these proteins are transcription factors, including initiation and elongation factors, which play differing roles in early and late stages of transcription. The mechanisms of transition from transcription initiation to elongation are not well understood in archaea, nor are the structures of the transcription factors involved. For transcription to occur in vitro, transcription factors TATA binding protein (TBP) and Transcription Factor B (TFB) are sufficient to allow RNA polymerase (RNAP) to synthesize RNA from template DNA. Another factor, Transcription …

Expanding Metabolic Diversity Of Two Archaeal Phyla: Nanoarchaeota And Korarchaeota, John Forad Kelley

Dissertations and Theses

Culture independent studies have revealed a greater diversity of Archaea than the two kingdoms initially defined by Carl Woese. Culturing species from the newly discovered archaeal lineages, as with the majority of microbes, has been difficult. To overcome the culturing dilemma, metagenomics is being used to reconstruct environmental genomes. Two metagenomic studies are presented in this thesis, with the aim of recovering newly proposed archaeal genomes from the Nanoarchaeota and Korarchaeota.

In the first study, a sediment sample, NZ13, was collected from a terrestrial New Zealand hot spring. Along with the sediment sample, two complex enrichments were sequenced on an …

A Genetic And Biochemical Analysis Of Sulfolobus Spindle-Shaped Virus 1, Eric Alexander Iverson

Dissertations and Theses

Viruses infecting the Archaea exhibit a tremendous amount of morphological and genetic diversity. This is especially true for crenarchaeal viruses from the family Fuselloviridae, which possess spindle-shaped capsids and genomes that harbor a great number of uncharacterized genes. The functions of these unidentified gene products are of interest as they have the potential to provide valuable insights into the fusellovirus infection cycle and archaeal viruses in general. In an effort to better characterize the genetic requirements of the Fuselloviridae, we have performed genetic and biochemical experiments using the best studied fusellovirus, Sulfolobus spindle-shaped virus 1 (SSV1).

A comprehensive …

The Role Of Pyrococcus Furiosus Transcription Factor E In Transcription Iniitiation, Robyn Lynn Eustis

Dissertations and Theses

All sequenced archaeal genomes encode a general transcription factor, TFE, which is highly conserved and homologous to the alpha subunit of the eukaryotic transcription factor TFIIE. TFE functions to increase promoter opening efficiency during transcription initiation, although the mechanism for this is unclear. The N-terminus of TFE contains a common DNA binding motif, a winged helix. At the tip of this winged helix is a highly conserved region of aromatic amino acids that is close to DNA during initiation. TFE activation can compensate for mutations in another transcription factor, TFB2, which is homologous to TFIIB. P. furiosus encodes two paralogs …

The Orientation Of The Pyrococcus Furiosus Transcription Factor Tfb2 In The Transcription Initiation Complex, Arati Bhattarai

Dissertations and Theses

The hyperthermophile archaeon, Pyrococcus furiosus encodes two eukaryotic TFIIB family proteins, TFB1 and TFB2. TFB1 is very similar to TFIIB in terms of sequence homology and function, whereas TFB2 is unusual as it is missing highly conserved sequences in its N-terminal domain that are present in TFIIB and TFB1. Despite this, TFB2 is effective in transcription process, albeit with lower efficiency compared to TFB1. Other archaea also contain multiple TFBs, but unlike Pyrococcus furiosus TFB2, these multiple TFBs have higher sequence homology to each other and have similar transcription efficiencies. Photochemical cross-linking experiments have shown that the B-reader of TFB …

Temperature Dependent Transcription Initiation In Archaea: Interplay Between Transcription Factor B And Promoter Sequence, Ming-Hsiao Wu

Dissertations and Theses

In Pyrococcus furiosus (Pfu), a hyperthermophile archaeon, two transcription factor Bs, TFB1 and TFB2 are encoded in the genomic DNA. TFB1 is the primary TFB in Pfu, and is homologous to transcription factor IIB (TFIIB) in eukaryotes. TFB2 is proposed to be a secondary TFB that is compared to TFB1, TFB2 lacks the conserved B-finger / B-reader / B-linker regions which assist RNA polymerase in transcription start site selection and promoter opening functions respectively. P. furiosus, like all Archaea, encodes a single transcription factor E (TFE), that is homologous to the N-terminus of transcription factor II …

The Family Fuselloviridae : Diversity And Replication Of A Hyperthermic Virus Infecting The Archaeon Genus Sulfolobus, Adam Joseph Clore

Dissertations and Theses

The virus family Fuselloviridae infects the hyperthermophilic and acidophilic Crenarchaeon genus Sulfolobus and has been isolated from terrestrial hotsprings worldwide. Two previously uncharacterized Fuselloviruses, SSV-13 and SSV-L1, were isolated and sequenced and are compared to the five fully sequenced viruses presently in the public databases. Conserved promoters in all viruses and similar putative origins of replication suggest that these viruses use a transcriptional and genomic replication program similar to the relatively well-characterized SSV1. Pairwise comparisons of conserved genes in the seven virus genomes show that, like its host Sulfolobus, these viruses' genetic divergence correlates with geographic separation. Genome rearrangements, horizontal …