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This Article Full Text Full Text (PDF) All Versions of this Article: fj.07-098111v1 22/7/2534    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Sekkali, B. Articles by Vleminckx, K. PubMed PubMed Citation Articles by Sekkali, B. Articles by Vleminckx, K.

Chicken β-globin insulator overcomes variegation of transgenes in Xenopus embryos

Belaïd Sekkali^*,,1,2, Hong Thi Tran^*,,1, Ellen Crabbe^*,, Christophe De Beule^*,, Frans Van Roy^*, and Kris Vleminckx^*,,3

^* Department for Molecular Biomedical Research, Flanders Institute for Biotechnologies, Ghent, Belgium; and

Department of Molecular Biology, Ghent University, Ghent, Belgium

³Correspondence: Department for Molecular Biomedical Research, VIB-Ghent University, Technologiepark 927, B-9052 Ghent, Belgium. E-mail: kris.vleminckx{at}dmbr.ugent.be

Chromatin structure and gene transcription regulation are intimately linked, and mosaic expression of randomly integrated transgenes into the genome is frequently observed. This variegation of transgene expression is likely due to the genomic integration site, which can affect the behavior of the integrated DNA sequence in a positive or a negative way. Insulators are a class of DNA elements that can protect genes from inappropriate signals emanating from their environment by acting as boundaries that prevent the spreading of nearby condensed chromatin that may otherwise silence expression. Here we show that transgenes escape this silencing in Xenopus laevis and Xenopus tropicalis embryos and that a stable, uniform, and heritable expression pattern is obtained when transgenes are flanked with tandem copies of the chicken β-globin 5'HS4 insulator. Our data also indicate that the insulator confers copy-number-dependent transgene expression and can increase transgene expression from weak regulatory elements. Hence, it will be an invaluable tool for generating stable lines expressing different levels of a particular coding sequence.—Sekkali, B., Tran, H. T., Crabbe, E., De Beule, C., Van Roy, F., Vleminckx, K. Chicken β-globin insulator overcomes variegation of transgenes in Xenopus embryos.

Key Words: transcriptional silencing • heterochromatin • position effect variegation