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Mol Cell Biol

Title:		Transposition of the yeast retroviruslike element Ty3 is dependent on the cell cycle
Author(s):		Menees TM; Sandmeyer SB;
Address:		"Department of Microbiology and Molecular Genetics, University of California, Irvine 92717"
Journal Title:		Mol Cell Biol
Year:		1994
Volume:		14
Issue:		12
Page Number:		8229 - 8240
DOI:		10.1128/mcb.14.12.8229-8240.1994
ISSN/ISBN:		0270-7306 (Print) 1098-5549 (Electronic) 0270-7306 (Linking)
Abstract:		"Host cell cycle genes provide important functions to retroviruses and retroviruslike elements. To define some of these functions, the cell cycle dependence of transposition of the yeast retroviruslike element Ty3 was examined. Ty3 is unique among retroviruslike elements because of the specificity of its integration, which occurs upstream of genes transcribed by RNA polymerase III. A physical assay for Ty3 transposition which takes advantage of this position-specific integration was developed. The assay uses PCR to amplify a product of Ty3 integration into a target plasmid that carries a modified tRNA gene. By using the GAL1 upstream activating sequence to regulate expression of Ty3, transposition was detected within one generation of cell growth after Ty3 transcription was initiated. This physical assay was used to show that Ty3 did not transpose when yeast cells were arrested in G1 during treatment with the mating pheromone alpha-factor. The restriction of transposition was not due to changes in transcription of either Ty3 or tRNA genes or to aspects of the mating pheromone response unrelated to cell cycle arrest. The block of the Ty3 life cycle was reversed when cells were released from G1 arrest. Examination of Ty3 intermediates during G1 arrest indicated that Ty3 viruslike particles were present but that reverse transcription of the Ty3 genomic RNA into double-stranded DNA had not occurred. In G1, the Ty3 life cycle is blocked after particle assembly but before the completion of reverse transcription"
Keywords:		"Base Sequence *Cell Cycle DNA Primers/chemistry DNA Replication DNA, Fungal/*genetics Mating Factor Molecular Sequence Data Peptides/pharmacology Recombination, Genetic *Retroelements Saccharomyces cerevisiae/*genetics;"
Notes:		"MedlineMenees, T M Sandmeyer, S B eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. 1994/12/01 Mol Cell Biol. 1994 Dec; 14(12):8229-40. doi: 10.1128/mcb.14.12.8229-8240.1994"