Extrachromosomal DNA of pea (Pisum sativum) root-tip cells replicates by strand displacement

Journal Article · Fri Apr 01 00:00:00 EST 1983 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.80.7.1933· OSTI ID:6389970

Krimer, D B; Van't Hof, J

In cultured pea roots there is extrachromosomal DNA associated with cells that differentiate from the G/sub 2/ phase of the cell cycle that is absent from those that differentiate from the G/sub 1/ phase. The authors examined this extrachromosomal DNA by electron microscopy and found that it consisted of three types: (i) double-stranded linear molecules with single-stranded branches (74%), (ii) double-stranded molecules without branches (26%), and (iii) free single-stranded molecules. The double-stranded molecules with or without branches were similar in length, having a modal length of 10-15 ..mu..m. The free single-stranded molecules were shorter and had a mean length of 3.8 ..mu..m. The length of the branches attached to the duplex molecules was only slightly less than that of the free form. The duplex molecules with branches were interpreted as configurations reflecting an ongoing strand-displacement process that results in free single-stranded molecules. Finally, measurements on duplex molecules with multiple branches suggested that the extrachromosomal DNA may exist in the form of tandemly repeated sequences. 8 references, 8 figures.

• Research Organization: Brookhaven National Lab. (BNL), Upton, NY (United States)
• OSTI ID: 6389970
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 80
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
DNA
MOLECULAR STRUCTURE
CELL DIFFERENTIATION
ELECTRON MICROSCOPY
EXPERIMENTAL DATA
MOLECULAR BIOLOGY
MOLECULES
PISUM
PLANT CELLS
ROOTS
BACTERIA
DATA
INFORMATION
LEGUMINOSAE
MICROORGANISMS
MICROSCOPY
NUCLEIC ACIDS
NUMERICAL DATA
ORGANIC COMPOUNDS
PLANTS
RHIZOBIUM
550300* - Cytology