Viruses or viruslike particles of eukaryotic algae are ubiquitous in aquatic
habitats, however, suprisingly little is known about them. The research presented here
focused on one such virus which infects a multicellular filamentous brown alga of the
genus Feldmannia. Although preliminary studies had been performed on the genome
structure of the Feldmannia sp. Virus (FsV), little was known. The purpose of this
study was to analyze the structure of the FsV genome in detail.
During the experiments aimed at mapping the FsV genome, cross-hybridization
was observed among five BamHI-fragments of the digested FsV DNA. Sequence
analysis of one of those fragments revealed the presence of 173 by direct repeats.
There are two FsV genomes of different size-classes (158 and 178 kbp). The 173 by
repeats in the cross-hybridizing BamHI-fragments were confined to a small region of
each virus genome. The number of these repeats in the 178 kbp genome was estimated
to be about 109 and in the 158 kbp genome to be about 41. in the 178 kbp genome,
the repeats are contained within a 22 kbp region and in the 1.58 kbp genome, the
repeats are contained within a 10 kbp region. These viruses are actively replicated in
sporophyte plants. A family of related 173 by direct repeats was discovered in an encrypted FsV
genome. The family of repeats estimated to be greater than 50 kbp in length were
found inserted into a protein kinase gene encoded within the 3.6 kbp viral BamHI-fragment
Z. Southern analysis indicates that these repeats in the encrypted FsV
genome are distinct from the previously characterized repeats in the amplified FsV
genome. The translated protein kinase shares highest homologies to the SNF1
subfamily of serine/threonine protein kinases and contains a potential
autophosphorylation site in a region unique to this protein kinase.
A DNA polymerase gene was identified in the FsV genome. The predicted
peptide sequence of the FsV DNA polymerase gene contains all of the conserved motifs
found in B-family (a-like) DNA polymerases. A TTTTTNT sequence motif shown to
be a transcription termination signal for Vaccinia virus early genes is found at the 3'
end of the DNA polymerase gene. Phylogenetic analysis of the FsV DNA polymerase
gene and other viral DNA polymerase genes indicates that FsV belongs to a group of
algal viruses recently defined as Phycodnaviridae. / Graduation date: 1998
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/34161 |
| Date | 18 June 1997 |
| Creators | Lee, Amy M. |
| Contributors | Meints, Russel H. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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