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Uracil can be used for drug delivery and as a pharmaceutical. When elemental fluorine reacts with uracil, they produce 5-fluorouracil. 5-Fluorouracil is an anticancer drug (antimetabolite) used to masquerade as uracil during the nucleic acid replication process. [2]
Uracil-DNA glycosylases are DNA repair enzymes that excise uracil residues from DNA by cleaving the N-glycosydic bond, initiating the base excision repair pathway. Uracil in DNA can arise either through the deamination of cytosine to form mutagenic U:G mispairs, or through the incorporation of dUMP by DNA polymerase to form U:A pairs. [18]
After a mutation occurs, the mutagenic threat of uracil propagates through any subsequent DNA replication steps. [6] Once unzipped, mismatched guanine and uracil pairs are separated, and DNA polymerase inserts complementary bases to form a guanine-cytosine (GC) pair in one daughter strand and an adenine-uracil (AU) pair in the other. [7]
These altered bases arise from the frequent hydrolysis of cytosine to uracil (see image) and hydrolysis of 5-methylcytosine to thymine, producing G:U and G:T base pairs. [16] If the improper uracils or thymines in these base pairs are not removed before DNA replication, they will cause transition mutations.
Cytosine (/ ˈ s aɪ t ə ˌ s iː n,-ˌ z iː n,-ˌ s ɪ n / [2] [3]) (symbol C or Cyt) is one of the four nucleotide bases found in DNA and RNA, along with adenine, guanine, and thymine (uracil in RNA). It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and a keto group ...
Similarly, the simple-ring structure of cytosine, uracil, and thymine is derived of pyrimidine, so those three bases are called the pyrimidine bases. [ 6 ] Each of the base pairs in a typical double- helix DNA comprises a purine and a pyrimidine: either an A paired with a T or a C paired with a G.
DNA methylation is the process in which a methyl group is added to either a cytosine or adenine. [22] This process causes the activation or inactivation of gene expression, thereby resulting in gene regulation in eukaryotic cells. DNA methylation process is also known to be involved in certain types of cancer formation.
The origin of replication (also called the replication origin) is a particular sequence in a genome at which replication is initiated. [1] Propagation of the genetic material between generations requires timely and accurate duplication of DNA by semiconservative replication prior to cell division to ensure each daughter cell receives the full ...