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Cellular and Molecular Basis of Human Biology
Published in Lawrence S. Chan, William C. Tang, Engineering-Medicine, 2019
Replication takes place when cells are divided and one copy of DNA will become two identical copies, just before the actual cell division occurs (Hillis et al. 2014). The human cell reproduction or division is under precisely controlled and occurred infrequently. Growth factors have the role of stimulate cells for division when it is needed for the entire organism. The enzymes involved in the DNA replication are: helicase, primase, DNA polymerase, and ligase. The basic steps of DNA replication are (Hillis et al. 2014): A large protein complex (pre-replication complex) binds specific site (called ori, or origin of replication) on DNA molecule.The binding on ori is followed by unwinding of the double-stranded DNA through the action of an enzyme helicase, leads to formation of replication fork.An enzyme primase binds to DNA and synthesizes a short RNA fragment (a primer) complementary to the DNA, initiating the replication process. The primase then releases from the DNA.A large enzyme complex, DNA polymerases bind to the site of primers of the two single-stranded DNA, start to synthesize the new DNA strands by adding one nucleotide at a time in a 5’ to 3’ direction, such that these two new DNA strands are synthesized in the opposite directions. DNA polymerases add deoxyribonucleoside triphosphates (dATP, dTTP, dGTP, and dCTP) to the new strand to “match” the DNA templates in a “A-T” and “G-C” fashion.A different DNA polymerase hydrolyses the RNA primer and replaces with DNA.A ligase fills the gap in the new strand between short segments.
MCM7 affects the cisplatin resistance of liver cancer cells and the development of liver cancer by regulating the PI3K/Akt signaling pathway
Published in Immunopharmacology and Immunotoxicology, 2022
DNA replication in eukaryotic cells is a highly regulated process. In order to ensure the stability of genes, multiple regulatory agents participate in the process of DNA replication [11]. Within human malignancies, mutations arising from DNA replication errors are an important basis of cancer development [12]. The MCM family is a vital component of the pre-replication complex involved in the replication initiation of DNA [13,14]. The dysfunction of MCM, especially MCM7, has been found in pituitary adenoma, breast cancer, gastric cancer, and esophageal squamous cell carcinoma [15–19].
Cyclin-dependent kinase inhibition and its intersection with immunotherapy in breast cancer: more than CDK4/6 inhibition
Published in Expert Opinion on Investigational Drugs, 2022
Xianan Guo, Huihui Chen, Yunxiang Zhou, Lu Shen, Shijie Wu, Yiding Chen
As a kinase, the CDK12/cyclin K complex restricts the association of cyclin E1 with CDK2 by phosphorylating cyclin E1 at Ser366, and this promotes pre-replicative complex assembly in the G1 phase that is crucial for cell proliferation and genomic stability [47]. Therefore, CDK12 is an important factor in regulating cell cycle.