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Proc Natl Acad Sci U S A. 1997 Apr 1;94(7):3290-5.

Folate deficiency causes uracil misincorporation into human DNA and chromosome breakage: implications for cancer and neuronal damage.

Author information

1
Department of Cell and Molecular Biology, University of California, Berkeley 94720, USA.

Abstract

Folate deficiency causes massive incorporation of uracil into human DNA (4 million per cell) and chromosome breaks. The likely mechanism is the deficient methylation of dUMP to dTMP and subsequent incorporation of uracil into DNA by DNA polymerase. During repair of uracil in DNA, transient nicks are formed; two opposing nicks could lead to chromosome breaks. Both high DNA uracil levels and elevated micronucleus frequency (a measure of chromosome breaks) are reversed by folate administration. A significant proportion of the U.S. population has low folate levels, in the range associated with elevated uracil misincorporation and chromosome breaks. Such breaks could contribute to the increased risk of cancer and cognitive defects associated with folate deficiency in humans.

PMID:
9096386
PMCID:
PMC20362
[Indexed for MEDLINE]
Free PMC Article

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