title: The Sea Urchin sns5 Chromatin Insulator Shapes the Chromatin Architecture of a Lentivirus Vector Integrated in the Mammalian Genome.
abstract: Lentivirus vectors are presently the favorite vehicles for therapeutic gene transfer in hematopoietic cells. Nonetheless, these vectors integrate randomly throughout the genome, exhibiting variegation of transgene expression due to the spreading of heterochromatin into the vector sequences. Moreover, the cis-regulatory elements harbored by the vector could disturb the proper transcription of resident genes neighboring the integration site. The incorporation of chromatin insulators in flanking position to the transferred unit can alleviate both the above-mentioned dangerous effects, due to the insulator-specific barrier and enhancer-blocking activities. In this study, we report the valuable properties of the sea urchin-derived sns5 insulator in improving the expression efficiency of a lentivirus vector integrated in the mammalian erythroid genome. We show that these results neither reflect an intrinsic sns5 enhancer activity nor rely on the recruitment of the erythroid-specific GATA-1 factor to sns5. Furthermore, by using the Chromosome Conformation Capture technology, we report that a single copy of the sns5-insulated vector is specifically organized into an independent chromatin loop at the provirus locus. Our results not only provide new clues concerning the molecular mechanism of sns5 function in the erythroid genome but also reassure the use of sns5 to improve the performance of gene therapy vectors.
authors.affiliation: 1 Campus of Haematology Franco e Piera Cutino, Villa Sofia-Cervello Hospital , Palermo, Italy .
authors.forename: Elena
authors.initials: E
authors.lastname: Baiamonte
authors.affiliation: 2 Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo , Palermo, Italy .
authors.forename: Giovanni
authors.initials: G
authors.lastname: Spinelli
authors.affiliation: 1 Campus of Haematology Franco e Piera Cutino, Villa Sofia-Cervello Hospital , Palermo, Italy .
authors.forename: Aurelio
authors.initials: A
authors.lastname: Maggio
authors.affiliation: 1 Campus of Haematology Franco e Piera Cutino, Villa Sofia-Cervello Hospital , Palermo, Italy .
authors.forename: Santina
authors.initials: S
authors.lastname: Acuto
authors.affiliation: 2 Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo , Palermo, Italy .|3 Mediterranean Center for Human Health Advanced Biotechnologies (CHAB), University of Palermo , Palermo, Italy .
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Cavalieri
mesh_terms: D000818:Animals; D001681:Biological Assay; D045744:Cell Line, Tumor; D002843:Chromatin / Q000737:chemistry* / Q000378:metabolism; D050982:GATA1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D017930:Genes, Reporter; D005822:Genetic Vectors / Q000737:chemistry / Q000378:metabolism*; D016678:Genome; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D038101:Insulator Elements; D016086:Lentivirus / Q000235:genetics* / Q000378:metabolism; D007962:Leukocytes / Q000166:cytology / Q000378:metabolism; D051379:Mice; D012617:Sea Urchins / Q000737:chemistry* / Q000235:genetics; D014161:Transduction, Genetic; D019076:Transgenes
chemical_list: D002843:Chromatin; D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; D049452:Green Fluorescent Proteins
keywords: chromatin insulator; chromatin structure; gene therapy; lentivirus; transgene expression