title: Modulation of Moloney leukemia virus long terminal repeat transcriptional activity by the murine CD4 silencer in retroviral vectors.
abstract: We investigated whether CD4 gene regulatory sequences might be useful for developing transcriptionally targeted Moloney murine leukemia virus (Mo-MLV)-based retroviral vectors for gene expression specifically in CD4(+) cells. We could modulate Mo-MLV long terminal repeat (LTR) activity by inserting a 438-bp-long fragment containing the murine CD4 silencer in the LTR of the vector; both beta-galactosidase and green fluorescent protein reporter gene activities were strongly down-regulated in both murine and human CD8(+) cells, but not in CD4(+) lymphoid cell lines and freshly isolated lymphocytes transduced with this vector, compared with the findings using a control vector carrying wild-type LTRs. Titration experiments on NIH-3T3 cells revealed that inclusion of the CD4 silencer in the LTRs did not reduce the titer of the vectors. These findings indicate that a cellular silencer can be successfully included in retroviral vectors, where it maintains its transcription-regulatory function, thus suggesting a novel approach to transcriptional targeting.
authors.affiliation: IST-Biotechnology Section, Padua, Italy. indra@ux1.unipd.it
authors.forename: S
authors.initials: S
authors.lastname: Indraccolo
authors.forename: S
authors.initials: S
authors.lastname: Minuzzo
authors.forename: W
authors.initials: W
authors.lastname: Habeler
authors.forename: R
authors.initials: R
authors.lastname: Zamarchi
authors.forename: A
authors.initials: A
authors.lastname: Fregonese
authors.forename: W H
authors.initials: WH
authors.lastname: Günzburg
authors.forename: B
authors.initials: B
authors.lastname: Salmons
authors.forename: W
authors.initials: W
authors.lastname: Uckert
authors.forename: L
authors.initials: L
authors.lastname: Chieco-Bianchi
authors.forename: A
authors.initials: A
authors.lastname: Amadori
mesh_terms: D016475:3T3 Cells; D000818:Animals; D015704:CD4 Antigens / Q000235:genetics*; D015316:Genetic Therapy; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics; D008214:Lymphocytes / Q000378:metabolism; D051379:Mice; D008979:Moloney murine leukemia virus / Q000235:genetics*; D011401:Promoter Regions, Genetic; D020079:Terminal Repeat Sequences; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D015704:CD4 Antigens; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; D001616:beta-Galactosidase