Show simple item record

dc.contributor.authorGRAISER, MICHAEL ALAN
dc.date.accessioned2018-07-12T18:12:56Z
dc.date.available2018-07-12T18:12:56Z
dc.date.issued1983
dc.identifier.citationSource: Dissertation Abstracts International, Volume: 43-11, Section: B, page: 3477.
dc.identifier.urihttps://yulib002.mc.yu.edu/login?url=http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqm&rft_dat=xri:pqdiss:8307099
dc.identifier.urihttps://hdl.handle.net/20.500.12202/2820
dc.description.abstractA series of morphological revertants of a Moloney murine sarcoma virus-transformed NRK nonproducer line, 6 O('+)H('-), was analyzed. The 6 O('+)H('-) genome contains three complete stably integrated proviruses. Thus reversion might result from lesions in single cellular components rather than multiple proviruses. Microdensitometry reveals that hybridization results suggesting a 5' LTR deletion in one of the three 6 O('+)H('-) proviruses are instead due to comigrating restriction fragments. Such a phenomenon is best accounted for by proposing that one provirus was duplicated along with a stretch of flanking rat DNA. All revertants have lost an entire provirus with retention of the remaining two. Virus expression is similar in 6 O('+)H('-) and revertants where individual transcripts are visible in a heterogeneous background. Revertants contain a viral transcript not detected in 6 O('+)H('-), this 35S species apparantly containing genetic information of the full-length 30S viral genome plus other information. Revertant proviruses are no more methylated and presumably no less active than the 6 O('+)H('-) proviruses. Revertant susceptibility to retransformation by Mo-MSV superinfection rules out possible cellular defects in RNA processing or transforming gene target sites. Mo-MuLV superinfection rescues from revertants low titers of transformation-competent virus. A spontaneously arising retransformant contains an additional provirus maintained as an extrachromosomal episome. It is proposed that the 6 O('+)H('-) genome contains two expressed competent MSV proviruses and one which is competent and silent. Its silence is maintained in revertants, reversed by a rare DNA rearrangement causing retransformation. Reversion results from the loss of one competent provirus and the generation of a point mutation in the other rendering it defective. Mo-MuLV rescues defective virus which occasionally back-mutates to generate competent virus. The lesions characterizing revertants affect MSV proviruses and not host cell components. Analysis of transformed and revertant genomes suggests a role of flanking host sequences in regulating the expression of some of the multiple proviruses.
dc.publisherProQuest Dissertations & Theses
dc.subjectGenetics.
dc.titleREGULATION OF EXPRESSION OF MULTIPLY-INTEGRATED MOLONEY-MSV PROVIRAL SEQUENCES
dc.typeDissertation


Files in this item

FilesSizeFormatView

There are no files associated with this item.

This item appears in the following Collection(s)

Show simple item record