Project description:Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) persists as minichromosomes in the nuclei of hepatocytes and serves as the transcriptional template for viral RNAs. The cccDNA pool, characterized by a low copy number, poses challenges for cccDNA research. To accurately mimic the full-length sequences and structure of HBV cccDNA, we developed a novel method using an M13 phage-based system and deoxyribozyme to produce full-length single-strand DNA (ssDNA) corresponding to both the positive and negative strands of cccDNA. This method involves the cyclization of the ssDNA followed by the addition of T4 DNA ligase, thereby producing the cccDNA. The in vitro cyclized cccDNA, formed by M13 phage-derived single-stranded DNA (McccDNA), allows the formation of minichromosomes in transiently transfected hepatic cells, recapitulates key stages of the HBV life cycle, and effectively responds to multiple antiviral drugs. Additionally, McccDNA was observed to more accurately transcribe major viral RNAs than recombinant cccDNAs containing exogenous sequences, and was also able to organize nucleosomes in a sequence-specific manner, resembling those events during natural viral infection. In conclusion, McccDNA generated from single-stranded M13 phage DNA recapitulates key natural properties of HBV cccDNA, and serves as an authentic and promising model to study cccDNA minichromosomes functionality.
Project description:Rat iPS M13 cells had different gene expression level compared with that of the adult cells including rat bone marrow cells(BMC) and rat primary ear fibroblasts(PEF). This difference gave rat iPS M13 cells unique characteristics which could then be compared with other species' ES cells or iPS cells like human ES cells and mouse ES cells by the homologue genes comparison to show which species' ES cells or iPS cells were more competitive with the other.
