episome


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Related to episome: endogenote, episomal DNA

episome

 [ep´ĭ-sōm″]
in bacterial genetics, any accessory extrachromosomal replicating genetic element that can exist either autonomously or integrated with the chromosome.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

ep·i·some

(ep'i-sōm),
An extrachromosomal element (plasmid) that may either integrate into the bacterial chromosome of the host or replicate and function stably when physically separated from the chromosome.
[epi- + G. sōma, body (chromosome)]
Farlex Partner Medical Dictionary © Farlex 2012

episome

(ĕp′ĭ-sōm′)
n.
A segment of DNA in certain cells, especially bacterial cells, that can exist either autonomously in the cytoplasm or as part of a chromosome.

ep′i·so′mal adj.
ep·i·so′mal·ly adv.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

ep·i·some

(ep'i-sōm)
An extrachromosomal element (plasmid) that may either integrate into the bacterial chromosome of the host or replicate and function stably when physically separated from the chromosome.
[epi- + G. sōma, body (chromosome)]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

episome

a circular DNA molecule found in bacterial cells that can exist independently in the cell or can become integrated into the main CHROMOSOME. In recent times, episomes have been added to a general group of extrachromosomal factors called PLASMIDS.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
References in periodicals archive ?
Bocavirus episome in infected human tissue contains non-identical termini.
EBNA1 has been hypothesised to tether EPV episomes to host mitotic chromosomes and chromatin.
Furthermore, a naturally occurring LANA isoform (with a 76 amino acid truncation at the C-terminal end) was detected in KSHV-infected primary effusion lymphoma (PEL) cell lines, BCP-1 and BC-3, but this isoform was incapable of binding to KSHV episomes and therefore exhibited diffuse nuclear staining [66].
In Burkitt's lymphoma, EBV is typically found in a latent form in the B cells, with its episome expressing a pattern of gene transcripts which are composed of two small RNA molecules (the EBV encoded RNAs--EBERs) and the EB nuclear antigen 1 (EBNA1), so-called type I latency.
When bound to one region, EBNA1 helps initiate replication of the viral episome and the dispersal of the two copies into the daughter cells.
The HPV16 physical status was determined on the assumption that the E2 gene is disrupted in integrated viral genome, and confirmed using the rate of E2 to E6 copy number: if E2/E6 ratios >1, HPV16 belonged to the episome status, if 0<E2/E6 ratios<1, HPV16 belonged to the mix status (including episome and integration), and if E2/E6 ratios=0, HPV16 belonged to the integrated status (29-31).
Human papillomavirus type 31 oncoproteins E6 and E7 are required for the maintenance of episomes during the viral life cycle in normal human keratinocytes.
Most of the lesions maintain the virus as an episome and support complete virus replication cycle with tight regulation of viral gene expression.
Also, on analysis of EBV DNA in the tumors, features akin to those found in PTLD including unique EBV DNA episomes (EBV small RNA, EBER, and EBV nuclear antigen2 (EBNA-2)) were noted.
In this context, EBV episomes tend to be absent in immunocompetent PCNSL patients, and other mechanisms of disease induction might be responsible for lymphomagenesis [43].