Extrachromosomal supercoiled circular copies of mobile dispersed genetic elements mdg1, mdg3 and copia have been isolated from 67J25D and Kc lines of cultured Drosophila melanogaster cells. With the exception of the copia element in the line Kc, all circular molecules contain only one long terminal repeat. Both whole-length circular copies and molecules with deletion from the internal segment of the copia element have been detected in the line 67J25D. Mdg3-specific circular molecules in the line Kc are represented by the deleted molecules only. Similar copies of mdg3 are also present in chromosomal DNA of flies and cultured cells. The analysis of the mdg3 transcription in both cell lines suggests that extrachromosomal molecules of mdg may be created by reverse transcription.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC320178 | PMC |
| http://dx.doi.org/10.1093/nar/12.19.7517 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Droplet digital PCR technique is ultrasensitive for the quantification of covalently closed circular DNA in the blood of chronic HBV-infected patients.
Clin Res Hepatol Gastroenterol
January 2025
Department of Molecular and Cellular Medicine, Institute of Liver and Biliary Sciences, New Delhi, India. Electronic address:
Background: Covalently closed circular DNA (cccDNA) is a stable, episomal form of HBV DNA. cccDNA is a true marker for the intrahepatic events in controlled CHB infection. Quantifying cccDNA is critical for monitoring disease progression, and efficacy of anti-viral therapies.
View Article and Find Full Text PDFThe pathway to resolve dimeric forms distinguishes plasmids from megaplasmids in Enterobacteriaceae.
Nucleic Acids Res
January 2025
Laboratoire de Microbiologie et de Génétique Moléculaires, Centre de Biologie Intégrative, Université de Toulouse, CNRS, 165 Rue Marianne Grunberg-Manago, campus Paul Sabatier, 118, route de Narbonne, 31062, Toulouse Cedex, France.
Bacterial genomes contain a plethora of secondary replicons of divergent size. Circular replicons must carry a system for resolving dimeric forms, resulting from recombination between sister copies. These systems use site-specific recombinases.
View Article and Find Full Text PDFCharacterization of Hepatitis B Virus Transcripts in Chronically HBV-Infected Chimpanzees and Patients Treated with ARC-520 siRNA Demonstrates Transcriptional Silencing of cccDNA.
Viruses
December 2024
Department of Medicine & State Key Laboratory of Liver Research, School of Clinical Medicine, The University of Hong Kong, Hong Kong, China.
Full-length hepatitis B virus (HBV) transcripts of chimpanzees and patients treated with multidose (MD) HBV siRNA ARC-520 and entecavir (ETV) were characterized by single-molecule real-time (SMRT) sequencing, identifying multiple types of transcripts with the potential to encode HBx, HBsAg, HBeAg, core, and polymerase, as well as transcripts likely to be derived from dimers of dslDNA, and these differed between HBeAg-positive (HBeAg+) and HBeAg-negative (HBeAg-) individuals. HBV transcripts from the last follow-up ~30 months post-ARC-520 treatment were categorized from one HBeAg+ (one of two previously highly viremic patients that became HBeAg- upon treatment and had greatly reduced cccDNA products) and four HBeAg- patients. The previously HBeAg+ patient received a biopsy that revealed that he had 3.
View Article and Find Full Text PDFChromosome hitchhiking: a potential strategy adopted by the selfish yeast plasmids to ensure symmetric inheritance during cell division.
Biochem Soc Trans
December 2024
Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India.
The 2-micron plasmid residing within the host budding yeast Saccharomyces cerevisiae nucleus serves as a model system for understanding the mechanism of segregation and stable maintenance of circular endogenously present extrachromosomal DNA in eukaryotic cells. The plasmid is maintained at a high average copy number (40-60 copies per yeast cell) through generations despite there is no apparent benefit to the host. Notably, the segregation mechanism of 2-micron plasmid shares significant similarities with those of bacterial low-copy-number plasmids and episomal forms of viral genomes in mammalian cells.
View Article and Find Full Text PDFDifferential HBV RNA and HBcrAg patterns in untreated patients with chronic hepatitis delta.
J Hepatol
December 2024
Division of Gastroenterology and Hepatology, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy; CRC "A. M. and A. Migliavacca" Center for Liver Disease, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy; D-SOLVE consortium, an EU Horizon Europe funded project (No 101057917), Italy. Electronic address:
Background & Aims: Serum HBV RNA and hepatitis B core-related antigen (HBcrAg) levels have been proposed as useful biomarkers in the management of patients with HBV; however, their role in chronic hepatitis delta (CHD) is currently unknown.
Methods: Consecutive untreated patients with CHD were enrolled in a cross-sectional study in three EU centers. Clinical and virological characteristics were collected.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!