Plasmid copy number control: isolation and characterization of high-copy-number mutants of plasmid pE194.

The termini of Saccharomyces cerevisiae chromosomes consist of tracts of C1-3A (one to three cytosine and one adenine residue) sequences of approximately 450 base pairs in length. To gain insights into trans-acting factors at telomeres, high-copy-number linear and circular plasmids containing tracts of C1-3A sequences were introduced into S. cerevisiae. We devised a novel system to distinguish by color colonies that maintained the vector at 1 to 5, 20 to 50, and 100 to 400 copies per cell and used it to change the amount of telomeric DNA sequences per cell. An increase in the number of C1-3A sequences caused an increase in the length of telomeric C1-3A repeats that was proportional to plasmid copy number. Our data suggest that telomere growth is inhibited by a limiting factor(s) that specifically recognizes C1-3A sequences and that this factor can be effectively competed for by long tracts of C1-3A sequences at telomeres or on circular plasmids. Telomeres without this factor are exposed to processes that serve to lengthen chromosome ends.

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Nucleotide sequence of the cryptic plasmid pTT8 from Thermus thermophilus HB8 and isolation and characterization of its high-copy-number mutant

Plasmid ◽

10.1016/j.plasmid.2004.01.003 ◽

2004 ◽

Vol 51 (3) ◽

pp. 227-237 ◽

Cited By ~ 16

Author(s):

Goh Takayama ◽

Takehide Kosuge ◽

Hideaki Maseda ◽

Akira Nakamura ◽

Takayuki Hoshino

Keyword(s):

Nucleotide Sequence ◽

Copy Number ◽

Thermus Thermophilus ◽

Cryptic Plasmid ◽

High Copy Number ◽

Thermus Thermophilus Hb8 ◽

Isolation And Characterization

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Plasmid copy number control: an ever-growing story

Molecular Microbiology ◽

10.1046/j.1365-2958.2000.02005.x ◽

2002 ◽

Vol 37 (3) ◽

pp. 492-500 ◽

Cited By ~ 100

Author(s):

Gloria Del Solar ◽

Manuel Espinosa

Keyword(s):

Copy Number ◽

Plasmid Copy Number ◽

Plasmid Copy ◽

Copy Number Control

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Genetic dissection of centromere function.

Molecular and Cellular Biology ◽

10.1128/mcb.13.6.3156 ◽

1993 ◽

Vol 13 (6) ◽

pp. 3156-3166 ◽

Cited By ~ 10

Author(s):

I G Schulman ◽

K Bloom

Keyword(s):

Chromosome Segregation ◽

Copy Number ◽

Artificial Chromosome ◽

Plasmid Copy Number ◽

Genetic Dissection ◽

Negative Effects ◽

Plasmid Copy ◽

Complex Cells ◽

Copy Number Control

A system to detect a minimal function of Saccharomyces cerevisiae centromeres in vivo has been developed. Centromere DNA mutants have been examined and found to be active in a plasmid copy number control assay in the absence of segregation. The experiments allow the identification of a minimal centromere unit, CDE III, independently of its ability to mediate chromosome segregation. Centromere-mediated plasmid copy number control correlates with the ability of CDE III to assemble a DNA-protein complex. Cells forced to maintain excess copies of CDE III exhibit increased loss of a nonessential artificial chromosome. Thus, segregationally impaired centromeres can have negative effects in trans on chromosome segregation. The use of a plasmid copy number control assay has allowed assembly steps preceding chromosome segregation to be defined.

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