Cytosine in Biological News

New nucleotide could revolutionize epigenetics

... school has heard of adenine, thymine, guanine and cytosine the A,T,G and C that make up the DNA code. But ... 5-methylcytosine (5-mC), that sometimes replaces cytosine in the famous DNA double helix to regulate which ... is DNA methylation, which targets sites where cytosine precedes guanine in the DNA code. An enzyme ...

Covering the bases: Quantum effect may hold promise for low-cost DNA sequencing, sensor applications

... to determine the identities of the four nucleotide basesadenine, thymine, cytosine and guaninewhich make up the ladder rungs of the DNA's double helical ... up appropriate nucleotide pairs like jigsaw piecesadenine with thymine and cytosine with guanine. The scanning tunneling microscope used in the present ...

Einstein researcher receives NIH grant to explore epigenetic regulation of the human genome

... and map the two principal epigenetic control mechanisms: methylation of cytosine (one of four nucleic acids found in DNA) and modifications of histones ... into chromosomes). The methylation (addition of a methyl group, CH3) of cytosine switches genes off, which can be associated with certain diseases such as ...

A new way to assemble cells into 3-D microtissues

... is the complexity of the synthetic DNA sequence. The researchers can specify the complexity for example, from a simple repeat of two bases such as cytosine and adenine ... on one strand, which binds to a complementary repeating sequence of thymine and guanine ... on the other, up to ...

New computational technique allows comparison of whole genomes as easily as whole books

... using a reduced, two-letter alphabet - R for the purine nucleic acids, adenine and guanine, and Y for the pyrimidine nucleic acids, thymine and cytosine - to reduce the complexity of calculation. Using an optimal feature length of 18 base pairs, this test created a family tree identical to the ...

Gene switch sites found mainly on 'shores,' not just 'islands' of the human genome

... that cancer cells show. The long-time focus in methylation has been CpG islands, regions of the genome rich in the DNA building-block molecules cytosine and guanine. The reason is that these islands tend to occur near the "start" signal of a protein-coding gene, a place with the potential to affect ...

Researchers solve piece of large-scale gene silencing mystery

... 3 (DCL3), an enzyme that chops up RNA transcripts into smaller segments. These smaller fragments of RNA become siRNAs, which then guide the de novo cytosine methyltransferase , DRM2, to the targeted genes. DRM2 is required to put a methyl group, a chemical flag that signals for silencing, on ribosomal ...

Copy number variation may stem from replication misstep

... complementary strands that remain together because of the attraction between nucleotides. A or adenosine is always attracted to T (thymidine). C or cytosine is always attracted to G or guanine. When a cell divides, it must reproduce its DNA so that each cell that results from the division has the same ...

Researchers identify how to switch off cancer cell genes

... promoter, suggesting that epigenetic silencing may be accomplished by the stable placement of nucleosomes into previously vacant positions. DNA cytosine methylation'the addition of a group of specific chemicals to a stretch of DNA that can lock or silence a gene'may ultimately lead to silencing by ...

How did chemical constituents essential to life arise on primitive Earth?

... and Crick in 1953. DNA is shaped somewhat like a twisted ladder with the rungs anchored by matching pairs of only four bases: adenine, guanine, cytosine and thymine. The UGA chemists focused on adenine because of its relative prevalence on Earth and its formation in the dark in from simple ...

Researchers expand efforts to explore functional landscape of the human genome

... Parallel Sequencing Technology for the Epigenome. This team will work to develop high-throughput sequencing methods to analyze methylation of cytosine and to map histone modifications. Xiaoman Li, Ph.D.; Indiana University, Indianapolis; $870,000 (three years); Discovery of Cis-Regulatory ...

Finding that 1-in-a-billion that could lead to disease

... not normally found in DNA: uracil. Even water can cause DNA damage, says Stivers. Its not a fast reaction, but water does convert the occasional cytosine into an unwanted uracil. To figure out how the enzyme responsible for cutting unwanted uracils out of DNA works, Stivers and colleagues studied a ...

Novel mechanism for DNA replication discovered

... on the original strand of DNA then its partner, a cytosine base, will pair to it on the replicated strand. ... called Rev1 DNA polymerase itself codes for a cytosine to be placed on the replicating strand. The cytosine is inserted based upon the coding information in ...

Uncovering DNA's 'sweet' secret

... flexibility in how the bases (rungs of the ladder) bind. The bases in normal DNA adhere to a somewhat strict binding scheme - guanine (G) binds with cytosine (C) and adenine (A) binds with thymine (T). In this "Watson-Crick" basepairing, the G:C bonds are much stronger than A:T or any other bonds. "In ...

Pathway toward gene silencing described in plants

... chromatin remodeler DRD1 presumably bulldozes histones and other proteins out of the way to make the DNA accessible for methylation by the de novo cytosine methyltransferase, DRM2. A paradoxical aspect of the pathway is that siRNAs direct DNA methylation but DNA methylation is also required for the ...

Study finds 60 new genes controlled by DNA snippet

... was the CArG box. The nucleotide building blocks of DNA chains may contain any one of four nucleobases: adenine (A), thymine (T), guanine (G) and cytosine (C). Any sequence of code starting with 2 Cs, followed by any combination of 6 As or Ts, and ending in 2 Gs is a CArG box. According to Miano, ...

Dog genome sequenced

... view, but instead that they preferentially fracture within ancient 'hot spots.' These fragile 'hot spots' contain an unusual number of guanine and cytosine DNA bases and appear to suffer higher rates of mutation." SINEs of genetic diversity Another study appearing in the dog genome section of ...

Scientists fetch useful information from dog genome publications

... view, but instead that they preferentially fracture within ancient 'hot spots.' These fragile 'hot spots' contain an unusual number of guanine and cytosine DNA bases and appear to suffer higher rates of mutation." SINEs of genetic diversity Another study appearing in the dog genome section of ...

DNA size a crucial factor in genetic mutations, study finds

... long, twisted ladder where each rung consists of two molecules that form a base pair. DNA has four bases: adenosine (A), thymine (T), guanine (G) and cytosine (C). A always pairs with T, and G with C. To copy itself, the DNA molecule unwinds and splits. Either strand is now a template to build a new DNA ...

NYU and MSKCC research provides model for understanding chemically induced cancer initiation

... mutation hot spot. The change is brought about by the presence of a single methyl group (composed only of one carbon and three hydrogen atoms) on a cytosine base adjacent to the damaged site. Without this methyl group, the bulky chemical carcinogen resides at an external binding site in the minor groove ...

Sequencing of marine bacterium will help study of cell communication

... but it is still more closely related to them than other organisms. (Among the four nucleotides that make up DNA ?adenine, guanine, thymine, and cytosine (ATGC) ?'A' pairs with 'T' and 'G' pairs with 'C'. The more GC content, the more tightly DNA strands bind.) Despite the fact that it is a symbiont, ...