title: Generation dependent reduction of tTA expression in double transgenic NZL-2/tTA(CMV) mice.
abstract: Despite the overall successful application of the tet-system to regulate gene expression in vitro and in vivo, nothing is known so far about the long-term stability of this system in transgenic mice. In this study, mice of generation F2, F3, F4, or F10 of two independent tTA(CMV) transgenic lines were bred with NZL-2 mice containing a tTA-responsive bidirectional promoter that allows the simultaneous expression of two reporter genes encoding luciferase and beta-galactosidase. Analysis of the expression of transgenes in double transgenic mice revealed a dramatic reduction of tTA transactivator mRNA over time. As a consequence, the expression of both reporter genes was gradually reduced from generation to generation in tissues of embryonic and adult NZL-2/tTA(CMV) mice. Luciferase activity in NZL-2/tTA(CMV)(F10) mice was reduced 8-10-fold compared to NZL-2/ tTA(CMV)(F2) mice, and beta-galactosidase expression was no longer detectable. In summary, we describe the long-term instability of the tet-system in our NZL-2/tTA(CMV) double transgenic mice. The molecular basis of this observation and experimental tools to overcome this limitation need to be addressed in future.
authors.forename: L M
authors.initials: LM
authors.lastname: Fedorov
authors.forename: O Y
authors.initials: OY
authors.lastname: Tyrsin
authors.forename: O
authors.initials: O
authors.lastname: Sakk
authors.forename: A
authors.initials: A
authors.lastname: Ganscher
authors.forename: U R
authors.initials: UR
authors.lastname: Rapp
mesh_terms: D000375:Aging / Q000235:genetics; D000818:Animals; D015139:Blotting, Southern; D003433:Crosses, Genetic; D004622:Embryo, Mammalian / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D017930:Genes, Reporter / Q000235:genetics; D008156:Luciferases / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013752:Tetracycline / Q000378:metabolism*; D013997:Time Factors; D019076:Transgenes / Q000235:genetics*; D001616:beta-Galactosidase / Q000032:analysis / Q000235:genetics* / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D008156:Luciferases; D001616:beta-Galactosidase; D013752:Tetracycline