Characteristics of the adeno-associated virus preintegration site in human chromosome 19: open chromatin conformation and transcription-competent environment.
Adeno-associated virus (AAV) establishes latency in infected cells by integrating into the cellular genome, with a high preference for a unique region, called AAVS1, of the human chromosome 19. The AAV proteins Rep78 and -68 are postulated to initiate the site-specific integration process by binding to a Rep binding site (RBS) in AAVS1. We provide further evidence to corroborate this model by demonstrating that the AAVS1 RBS in human cell lines is located near a DNase I hypersensitive "open" chromatin region and therefore is potentially easily accessible to Rep proteins. This open conformation is maintained in transgenic rats which carry an AAVS1 3. 5-kb DNA fragment and are proficient for Rep-mediated site-specific integration. Interestingly, the core of the DNAse I hypersensitive site in AAVS1 corresponds to a sequence displaying transcriptional enhancer-like properties, suggesting that AAVS1 constitutes a transcription-competent environment. The implications of our findings for AAV physiology and gene therapy are discussed.
Lamartina
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S
Department of Genetics, Istituto di Ricerche di Biologia Molecolare, I.R.B.M.-Piero Angeletti, 00040 Pomezia (Rome), Italy.
Sporeno
E
E
Fattori
E
E
Toniatti
C
C
D000818:Animals; D030801:Animals, Genetically Modified; D002460:Cell Line; D002843:Chromatin / Q000737:chemistry* / Q000378:metabolism; D002888:Chromosomes, Human, Pair 19 / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D000229:Dependovirus / Q000235:genetics* / Q000378:metabolism; D015316:Genetic Therapy; D006367:HeLa Cells; D006801:Humans; D051381:Rats; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000378:metabolism; D016662:Virus Integration
D002843:Chromatin; D004268:DNA-Binding Proteins; D014764:Viral Proteins; C068734:rep proteins, Adeno-associated virus 2