This article may be too technical for most readers to understand.(February 2021) |
Names | |
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IUPAC name 5-Bromo-2′-deoxyuridine | |
Systematic IUPAC name 5-Bromo-1-[(2R,4S,5R)-4-hydroxy-5-(hydroxymethyl)oxolan-2-yl]pyrimidine-2,4(1H,3H)-dione | |
Identifiers | |
3D model (JSmol) | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.000.378 |
MeSH | Bromodeoxyuridine |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
C9H11BrN2O5 | |
Molar mass | 307.100 g·mol−1 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
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 [1] and has been studied as a radiosensitizer [2] and diagnostic tool in people with cancer. [3]
During the S phase of the cell cycle (when DNA replication occurs), BrdU can be incorporated in place of thymidine in newly synthesized DNA molecules of dividing cells. [4] Cells that have recently performed DNA replication or DNA repair can be detected with antibodies specific for BrdU using techniques such as immunohistochemistry or immunofluorescence. [5] BrdU-labelled cells in humans can be detected up to two years after BrdU infusion. [6]
Because BrdU can replace thymidine during DNA replication, it can cause mutations, and its use is therefore potentially a health hazard.[ citation needed ] However, because it is neither radioactive nor myelotoxic at labeling concentrations, it is widely preferred for in vivo studies of cancer cell proliferation. [7] [8] However, at radiosensitizing concentrations, BrdU becomes myelosuppressive, thus limiting its use for radiosensitizing. [2]
BrdU differs from thymidine in that BrdU substitutes a bromine atom for thymidine's CH3 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. [9] [10]
Bromodeoxyuridine releases gene silencing caused by DNA methylation. [11]
BrdU can also be used to identify microorganisms that respond to specific carbon substrates in aquatic [12] and soil [13] 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. [14] 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 included in RNA as a complement to BrdU. [15]
Thymidine, also known as deoxythymidine, deoxyribosylthymine, or thymine deoxyriboside, is a pyrimidine deoxynucleoside. Deoxythymidine is the DNA nucleoside T, which pairs with deoxyadenosine (A) in double-stranded DNA. In cell biology it is used to synchronize the cells in G1/early S phase. The prefix deoxy- is often left out since there are no precursors of thymine nucleotides involved in RNA synthesis.
A salvage pathway is a pathway in which a biological product is produced from intermediates in the degradative pathway of its own or a similar substance. The term often refers to nucleotide salvage in particular, in which nucleotides are synthesized from intermediates in their degradative pathway.
Thymidine kinase is an enzyme, a phosphotransferase : 2'-deoxythymidine kinase, ATP-thymidine 5'-phosphotransferase, EC 2.7.1.21. It can be found in most living cells. It is present in two forms in mammalian cells, TK1 and TK2. Certain viruses also have genetic information for expression of viral thymidine kinases. Thymidine kinase catalyzes the reaction:
Hoechst stains are part of a family of blue fluorescent dyes used to stain DNA. These bis-benzimides were originally developed by Hoechst AG, which numbered all their compounds so that the dye Hoechst 33342 is the 33,342nd compound made by the company. There are three related Hoechst stains: Hoechst 33258, Hoechst 33342, and Hoechst 34580. The dyes Hoechst 33258 and Hoechst 33342 are the ones most commonly used and they have similar excitation–emission spectra.
Nucleoside analogues are structural analogues of a nucleoside, which normally contain a nucleobase and a sugar. Nucleotide analogues are analogues of a nucleotide, which normally has one to three phosphates linked to a nucleoside. Both types of compounds can deviate from what they mimick in a number of ways, as changes can be made to any of the constituent parts. They are related to nucleic acid analogues.
HAT Medium is a selection medium for mammalian cell culture, which relies on the combination of aminopterin, a drug that acts as a powerful folate metabolism inhibitor by inhibiting dihydrofolate reductase, with hypoxanthine and thymidine which are intermediates in DNA synthesis. The trick is that aminopterin blocks DNA de novo synthesis, which is absolutely required for cell division to proceed, but hypoxanthine and thymidine provide cells with the raw material to evade the blockage, provided that they have the right enzymes, which means having functioning copies of the genes that encode them.
Floxuridine is an oncology drug that belongs to the class known as antimetabolites. Specifically, floxuridine is a pyrimidine analog, classified as a deoxyuridine. The drug is usually administered via an artery, and most often used in the treatment of colorectal cancer. The quality of life and survival rates of individuals that receive continuous hepatic artery infusion of floxuridine for colorectal cancer metastases is significantly higher than control groups. Floxuridine can also be prescribed for the treatment of kidney and stomach cancers. In vitro uses of floxuridine include 5-minute treatments of fluorouracil, floxuridine, and mitomycin to increase cell proliferation in Tenon's capsule fibroblasts.
The immortal DNA strand hypothesis was proposed in 1975 by John Cairns as a mechanism for adult stem cells to minimize mutations in their genomes. This hypothesis proposes that instead of segregating their DNA during mitosis in a random manner, adult stem cells divide their DNA asymmetrically, and retain a distinct template set of DNA strands in each division. By retaining the same set of template DNA strands, adult stem cells would pass mutations arising from errors in DNA replication on to non-stem cell daughters that soon terminally differentiate. Passing on these replication errors would allow adult stem cells to reduce their rate of accumulation of mutations that could lead to serious genetic disorders such as cancer.
Thymidylate synthase (TS) is an enzyme that catalyzes the conversion of deoxyuridine monophosphate (dUMP) to deoxythymidine monophosphate (dTMP). Thymidine is one of the nucleotides in DNA. With inhibition of TS, an imbalance of deoxynucleotides and increased levels of dUMP arise. Both cause DNA damage.
Thymidine kinase 1, soluble, is a human thymidine kinase.
Thymidine phosphorylase is an enzyme that is encoded by the TYMP gene and catalyzes the reaction:
Proliferation, as one of the hallmarks and most fundamental biological processes in tumors, is associated with tumor progression, response to therapy, and cancer patient survival. Consequently, the evaluation of a tumor proliferative index has clinical significance in characterizing many solid tumors and hematologic malignancies. This has led investigators to develop different technologies to evaluate the proliferation index in tumor samples. The most commonly used methods in evaluating a proliferative index include mitotic indexing, thymidine-labeling index, bromodeoxyuridine assay, the determination of fraction of cells in various phases of cell cycle, and the immunohistochemical evaluation of cell cycle-associated proteins.
5-Ethynyl-2′-deoxyuridine (EdU) is a thymidine analogue which is incorporated into the DNA of dividing cells. EdU is used to assay DNA synthesis in cell culture and detect cells in embryonic, neonatal and adult animals which have undergone DNA synthesis. Whilst at high doses it can be cytotoxic, this molecule is now widely used to track proliferating cells in multiple biological systems.
Cell cycle analysis by DNA content measurement is a method that most frequently employs flow cytometry to distinguish cells in different phases of the cell cycle. Before analysis, the cells are usually permeabilised and treated with a fluorescent dye that stains DNA quantitatively, such as propidium iodide (PI) or 4,6-diamidino-2-phenylindole (DAPI). The fluorescence intensity of the stained cells correlates with the amount of DNA they contain. As the DNA content doubles during the S phase, the DNA content (and thereby intensity of fluorescence) of cells in the G0 phase and G1 phase (before S), in the S phase, and in the G2 phase and M phase (after S) identifies the cell cycle phase position in the major phases (G0/G1 versus S versus G2/M phase) of the cell cycle. The cellular DNA content of individual cells is often plotted as their frequency histogram to provide information about relative frequency (percentage) of cells in the major phases of the cell cycle.
5-Bromouridine is a uridine derivative with a bromo substituent at the fifth carbon. BrUrd is incorporated into RNA and can be detected immunocytochemically and analysed by cytometry. It causes DNA damage through base substitution and increases the number of mutations.
Single-cell sequencing examines the nucleic acid sequence information from individual cells with optimized next-generation sequencing technologies, providing a higher resolution of cellular differences and a better understanding of the function of an individual cell in the context of its microenvironment. For example, in cancer, sequencing the DNA of individual cells can give information about mutations carried by small populations of cells. In development, sequencing the RNAs expressed by individual cells can give insight into the existence and behavior of different cell types. In microbial systems, a population of the same species can appear genetically clonal. Still, single-cell sequencing of RNA or epigenetic modifications can reveal cell-to-cell variability that may help populations rapidly adapt to survive in changing environments.
Single-cell DNA template strand sequencing, or Strand-seq, is a technique for the selective sequencing of a daughter cell's parental template strands. This technique offers a wide variety of applications, including the identification of sister chromatid exchanges in the parental cell prior to segregation, the assessment of non-random segregation of sister chromatids, the identification of misoriented contigs in genome assemblies, de novo genome assembly of both haplotypes in diploid organisms including humans, whole-chromosome haplotyping, and the identification of germline and somatic genomic structural variation, the latter of which can be detected robustly even in single cells.
Thymidine kinase is an enzyme, a phosphotransferase : 2'-deoxythymidine kinase, ATP-thymidine 5'-phosphotransferase, EC 2.7.1.21 that catalyzes the reaction:
Marine viruses are defined by their habitat as viruses that are found in marine environments, that is, in the saltwater of seas or oceans or the brackish water of coastal estuaries. Viruses are small infectious agents that can only replicate inside the living cells of a host organism, because they need the replication machinery of the host to do so. They can infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea.
Adult neurogenesis is the process in which new neurons are born and subsequently integrate into functional brain circuits after birth and into adulthood. Avian species including songbirds are among vertebrate species that demonstrate particularly robust adult neurogenesis throughout their telencephalon, in contrast with the more limited neurogenic potential that are observed in adult mammals after birth. Adult neurogenesis in songbirds is observed in brain circuits that underlie complex specialized behavior, including the song control system and the hippocampus. The degree of postnatal and adult neurogenesis in songbirds varies between species, shows sexual dimorphism, fluctuates seasonally, and depends on hormone levels, cell death rates, and social environment. The increased extent of adult neurogenesis in birds compared to other vertebrates, especially in circuits that underlie complex specialized behavior, makes birds an excellent animal model to study this process and its functionality. Methods used in research to track adult neurogenesis in birds include the use of thymidine analogues and identifying endogenous markers of neurogenesis. Historically, the discovery of adult neurogenesis in songbirds substantially contributed to establishing the presence of adult neurogenesis and to progressing a line of research tightly associated with many potential clinical applications.