The work in this thesis has provided conclusive genetic evidence
that "panhandle" intermediates form during adenovirus replication.
Adenovirus chromosomes lacking 51 by from their left -hand termini
are infectious and capable of regenerating the missing origin
sequence. Yet if an entire inverted terminal repeat is removed, the
adenovirus chromosome is no longer viable. This first suggested, but
did not prove, that "panhandles" formed during adenovirus
replication. Homologous recombination or postreplicative overlap
recombination could generate the same outcome. Analysis of the
segregation of markers in the inverted repeats of adenovirus
minichromosomes shows that homologous recombination does not
mediate end repair. A special case was also found where
postreplicative overlap recombination failed to transfer sequences
between the inverted repeats, but similar molecules could exchange
sequence information during "panhandle" formation. The exchange of
information between inverted repeats is referred to as sequence
conversion. A number of length and/or orientation constraints on
sequence conversion during adenovirus DNA replication were
identified. A length- and orientation-dependent constraint was found
for gap filling close to "panhandle" loops. Polymerization towards the
loop could occur even when the gap was only 6 by away. In contrast,
polymerization away from the "panhandle" loop at a gap at 6 bp, did not
take place. This steric constraint could reflect an asymmetry in the
action of adenovirus DNA polymerase. A similar length and/or
orientation dependent constraint was found for the removal of bulges (3
by and 4 by mismatches). Incision in the bulge of the 5' inverted repeat
caused a block to the completion of sequence conversion at that site.
When the bulge was in the 3' inverted repeat, a length requirement for
successful removal was demonstrated. When 6 by or 39 by separated
the bulge from the "panhandle" loop, removal of the bulge was not
detected. When the distance was 79 bp, 184 bp, or 217 bp, bulges were
successfully removed. The molecular basis for this obstruction
remains to be determined. Moreover, incision in bulges located in the
3' inverted repeat triggers directional coconversion. Finally, small
loops placed close to the site of polymerization did not cause the same
length and orientation dependent constraints as did the "panhandle"
loop. / Graduation date: 1991
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37101 |
| Date | 30 April 1991 |
| Creators | Bennett, Kelly L. |
| Contributors | Pearson, George D. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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