Home About us Contact
|
Home About us Contact | ||
|
|
||
Genomic Integration (genomic + integration)
Selected AbstractsViral load and genomic integration of HPV 16 in cervical samples from HIV-1-infected and uninfected women in Burkina FasoJOURNAL OF MEDICAL VIROLOGY, Issue 6 2007Marie-Noelle Didelot Rousseau Abstract The relationships between human papillomavirus type 16 (HPV 16) viral load, HPV 16 integration status, human immunodeficiency virus type 1 (HIV-1) status, and cervical cytology were studied among women enrolled in a cohort of female sex workers in Burkina Faso. The study focused on 24 HPV 16-infected women. The HPV 16 viral load in cervical samples was determined by real-time PCR. Integration ratio was estimated as the ratio between E2 and E6 genes DNA copy numbers. Integrated HPV16 viral load was defined as the product of HPV 16 viral load by the integration ratio. High HPV 16 viral load and high integration ratio were more frequent among women with squamous intraepithelial lesions compared with women with normal cytology (33% vs. 11%, and 33% vs. 0%, respectively), and among women with high-grade squamous intraepithelial lesions compared with women without high-grade squamous intraepithelial lesions (50% vs. 17%, and 50% vs. 11%, respectively). High HPV 16 DNA load, but not high integration ratio, was also more frequent among HIV-1-positive women (39% vs. 9%; and 23% vs. 18%, respectively). The absence of statistical significance of these differences might be explained by the small study sample size. High-integrated HPV 16 DNA load was significantly associated with the presence of high-grade squamous intraepithelial lesions (50% vs. 5%, P,=,0.03) in univariate and multivariate analysis (adjusted odds-ratio: 19.05; 95% confidence interval (CI), 1.11,328.3, P,=,0.03), but not with HIV-1 or other high-risk HPV types (HR-HPV). Integrated HPV 16 DNA load may be considered as a useful marker of high-grade cervical lesions in HPV 16-infected women. J. Med. Virol. 79: 766,770, 2007. © 2007 Wiley-Liss, Inc. [source] The RecJ DNase strongly suppresses genomic integration of short but not long foreign DNA fragments by homology-facilitated illegitimate recombination during transformation of Acinetobacter baylyiMOLECULAR MICROBIOLOGY, Issue 3 2007Klaus Harms Summary Homology-facilitated illegitimate recombination (HFIR) promotes genomic integration of foreign DNA with a single segment homologous to the recipient genome by homologous recombination in the segment accompanied by illegitimate fusion of the heterologous sequence. During natural transformation of Acinetobacter baylyi HFIR occurs at about 0.01% of the frequency of fully homologous recombination. The role of the 5, single-strand-specific exonuclease RecJ in HFIR was investigated. Deletion of recJ increased HFIR frequency about 20-fold compared with wild type while homologous recombination was not affected. Illegitimate fusion sites were predominantly located within 360 nucleotides away from the homology whereas in wild type most fusion sites were distal (500,2500 nucleotides away). RecJ overproduction reduced the HFIR frequency to half compared with wild type, and transformants with short foreign DNA segments were diminished, leading to on average 866 foreign nucleotides integrated per event (682 in wild type, 115 in recJ). In recJ always the 3, ends of donor DNA were integrated at the homology whereas in wild type these were 3, or 5,. RecJ apparently suppresses HFIR by degrading 5, non-homologous DNA tails at the post-synaptic stage. We propose that the RecJ activity level controls the HFIR frequency during transformation and the amount of foreign DNA integrated per event. [source] Diverse genomic integration of a lentiviral vector developed for the treatment of Wiskott,Aldrich syndromeTHE JOURNAL OF GENE MEDICINE, Issue 8 2009Julie Mantovani Abstract Background The genomic integration of a lentiviral vector developed for the treatment of Wiskott,Aldrich syndrome (WAS) was assessed by localizing the vector insertion sites (IS) in a murine model of gene therapy for the disease. Methods Transduced hematopoietic progenitor cells were transplanted into mice or cultured in vitro. The IS were determined in the genomic DNA from blood, the bone marrow of the animals and from cultured cells. Results Sequencing vector,genomic DNA junctions yielded more than 150 IS of which 50,70% were located in transcription units. To obtain additional sequences from the population of cultured cells, we used a vector-tag concatenation technique providing 190 additional IS. Altogether, the profiles confirmed the bias for integration in transcription units. The vector did not congregate as hotspots and did not appear to target specific categories of genes. The diversity of the IS reflected the initial marking of a polyclonal population of cells. However, relatively few vector IS were found in vivo because only 30,40 unique IS were identified in each mouse using this approach. Although four to ten IS were shared by the blood and bone marrow, no common IS was found between mice or between any mouse and the cultured cells. Conclusions Taken as a whole, the pattern of genomic insertion of the WAS lentiviral vector was diverse and similar to that previously described for other HIV-1-derived lentiviral vectors. Testing cells destined for transplantation is unlikely to predict specific IS to be selected in vivo. Copyright © 2009 John Wiley & Sons, Ltd. [source] Phage ,C31 integrase-mediated genomic integration of the common cytokine receptor gamma chain in human T-cell linesTHE JOURNAL OF GENE MEDICINE, Issue 5 2006Yoshinori Ishikawa Abstract Background X-linked severe combined immunodeficiency (SCID-X1, X-SCID) is a life-threatening disease caused by a mutated common cytokine receptor , chain (,c) gene. Although ex vivo gene therapy, i.e., transduction of the ,c gene into autologous CD34+ cells, has been successful for treating SCID-X1, the retrovirus vector-mediated transfer allowed dysregulated integration, causing leukemias. Here, to explore an alternative gene transfer methodology that may offer less risk of insertional mutagenesis, we employed the ,C31 integrase-based integration system using human T-cell lines, including the ,c-deficient ED40515(-). Methods A ,C31 integrase and a neor gene expression plasmid containing the ,C31 attB sequence were co-delivered by electroporation into Jurkat cells. After G418 selection, integration site analyses were performed using linear amplification mediated-polymerase chain reaction (LAM-PCR). ED40515(-) cells were also transfected with a ,c expression plasmid containing attB, and the integration sites were determined. IL-2 stimulation was used to assess the functionality of the transduced ,c in an ED40515(-)-derived clone. Results Following co-introduction of the ,C31 integrase expression plasmid and the plasmid carrying attB, the efficiency of integration into the unmodified human genome was assessed. Several integration sites were characterized, including new integration sites in intergenic regions on chromosomes 13 and 18 that may be preferred in hematopoietic cells. An ED40515(-) line bearing the integrated ,c gene exhibited stable expression of the ,c protein, with normal IL-2 signaling, as assessed by STAT5 activation. Conclusions This study supports the possible future use of this ,C31 integrase-mediated genomic integration strategy as an alternative gene therapy approach for treating SCID-X1. Copyright © 2006 John Wiley & Sons, Ltd. [source] | ||||||||||