Cell growth briefly at M phase when the nucleus and then the cell divide in two. The process of cell division, called cell cycle, has four major parts called phases. The first part, called G phase is marked by synthesis of various enzymes that are required for DNA replication. The second part of the cell cycle is the S phase, where DNA replication produces two identical sets of chromosomes. The third part is the G phase in which a significant protein synthesis occurs, mainly involving the production of microtubules that are required during the process of division, called mitosis. The fourth phase,
Merkel cell polyomavirus another study, 45 of 53 (85%) Merkel cell tumors were positive. Sequencing of the virus from Merkel cell cancers reveals that it generally has tumor-specific mutations that truncate the MCV T antigen. These mutations (which are not found in native virus obtained from nontumor sites) eliminate the T antigen helicase, preventing the integrated virus from replicating independently from the host cancer cell. The tumor is a "dead-end host" for MCV. Normally, the virus exists as circular episome (or plasmid) within the cell and its DNA is packaged into viral capsids and transmitted to other cells. In tumors, the viral DNA