tailieunhanh - Báo cáo y học: "Substitution of adeno-associated virus Rep protein binding and nicking sites with human Chromosome 19 sequences"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Substitution of adeno-associated virus Rep protein binding and nicking sites with human Chromosome 19 sequences | McAlister and Owens Virology Journal 2010 7 218 http content 7 1 218 VIROLOGY JOURNAL RESEARCH Open Access Substitution of adeno-associated virus Rep protein binding and nicking sites with human Chromosome 19 sequences Victor J McAlister Roland A Owens Abstract Background Adeno-associated virus type 2 AAV2 preferentially integrates its DNA at a 2 kb region of human chromosome 19 designated AAVS1 also known as MBS85 . Integration at AAVS1 requires the AAV2 replication Rep proteins and a DNA sequence within AAVS1 containing a 16 bp Rep recognition sequence RRS and closely spaced Rep nicking site also referred to as a terminal resolution site or trs . The AAV2 genome is flanked by inverted terminal repeats ITRs . Each ITR contains an RRS and closely spaced trs but the sequences differ from those in AAVS1. These ITR sequences are required for replication and packaging. Results In this study we demonstrate that the AAVS1 RRS and trs can function in AAV2 replication packaging and integration by replacing a 61 bp region of the AAV2 ITR with a 49 bp segment of AAVS1 DNA. Modifying one or both ITRs did not have a large effect on the overall virus titers. These modifications did not detectably affect integration at AAVS1 as measured by semi-quantitative nested PCR assays. Sequencing of integration junctions shows the joining of the modified ITRs to AAVS1 sequences. Conclusions The ability of these AAVS1 sequences to substitute for the AAV2 RRS and trs provides indirect evidence that the stable secondary structure encompassing the trs is part of the AAV2 packaging signal. Background Adeno-associated viruses AAVs are mammalian parvoviruses that typically require a helper virus such as an adenovirus or herpesvirus for productive replication 1 . Multiple AAV serotypes have been described. The most detailed information is available for AAV serotype 2 AAV2 the first human isolate. In the absence of helper virus AAV2 preferentially integrates into a region of .