Bromodeoxyuridine (5-bromo-2'-deoxyuridine, BrdU, BUdR, BrdUrd, broxuridine) is a synthetic
nucleoside analogue with a chemical structure similar to
thymidine. BrdU is commonly used to study
cell proliferation in living tissues and has been studied as a
radiosensitizer and
diagnostic tool in people with
cancer.
During the
S phase of the
cell cycle
The cell cycle, or cell-division cycle, is the sequential series of events that take place in a cell (biology), cell that causes it to divide into two daughter cells. These events include the growth of the cell, duplication of its DNA (DNA re ...
(when
DNA replication occurs), BrdU can be incorporated in place of thymidine in newly synthesized
DNA molecules of dividing cells.
Cells that have recently performed DNA replication or
DNA repair can be detected with
antibodies specific for BrdU using techniques such as
immunohistochemistry
Immunohistochemistry is a form of immunostaining. It involves the process of selectively identifying antigens in cells and tissue, by exploiting the principle of Antibody, antibodies binding specifically to antigens in biological tissues. Alber ...
or
immunofluorescence.
BrdU-labelled cells in humans can be detected up to two years after BrdU infusion.
Because BrdU can replace
thymidine during DNA replication, it can cause
mutations, and its use is therefore potentially a health hazard. However, because it is neither
radioactive nor
myelotoxic at labeling concentrations, it is widely preferred for ''in vivo'' studies of
cancer cell proliferation.
However, at
radiosensitizing concentrations, BrdU becomes myelosuppressive, thus limiting its use for radiosensitizing.
BrdU differs from
thymidine in that BrdU substitutes a
bromine atom for
thymidine's CH
3 group. The Br substitution can be used in X-ray diffraction experiments in crystals containing either DNA or RNA. The Br atom acts as an anomalous scatterer and its larger size will affect the crystal's X-ray diffraction enough to detect
isomorphous differences as well.
Bromodeoxyuridine releases gene silencing caused by DNA methylation.
BrdU can also be used to identify microorganisms that respond to specific carbon substrates in aquatic and soil environments. A carbon substrate added to the incubations of environmental samples will cause the growth of microorganisms that can utilize that substrate. These microorganisms will then incorporate BrdU into their DNA as they grow. Community DNA can then be isolated and BrdU-labeled DNA purified using an immunocapture technique. Subsequent sequencing of the labeled DNA can then be used to identify the microbial taxa that participated in the degradation of the added carbon source.
However, it is not certain whether all microbes present in an environmental sample can incorporate BrdU into their biomass during ''de novo'' DNA synthesis. Therefore, a group of microorganisms may respond to a carbon source but go undetected using this technique. Additionally, this technique is biased towards identifying microorganisms with A- and T-rich genomes.
DNA with BrdU transcribes as usual DNA, with
guanine
Guanine () (symbol G or Gua) is one of the four main nucleotide bases found in the nucleic acids DNA and RNA, the others being adenine, cytosine, and thymine ( uracil in RNA). In DNA, guanine is paired with cytosine. The guanine nucleoside ...
included in RNA as a complement to BrdU.
See also
*
5-Bromouracil
*
5-Bromouridine
*
5-Ethynyl-2'-deoxyuridine
*
Trypan blue
References
{{Reflist, 2
External links
BrdU at OpenWetWareBrdU Modifications at IDT DNA
Genetics techniques
Nucleosides
Staining dyes
Organobromides
Pyrimidinediones
Hydroxymethyl compounds