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ZFIN ID: ZDB-PUB-130927-4
Chicken β-globin insulators fail to shield the nkx2.5 promoter from integration site effects in zebrafish
Grajevskaja, V., Balciuniene, J., and Balciunas, D.
Date: 2013
Source: Molecular genetics and genomics : MGG   288(12): 717-25 (Journal)
Registered Authors: Balciunas, Darius, Balciuniene, Jorune
Keywords: zebrafish, transposon, position effect, insulator, transgenesis, nkx2.5
MeSH Terms:
  • Animals
  • Animals, Genetically Modified
  • Chickens/genetics*
  • DNA Transposable Elements/physiology
  • Embryo, Nonmammalian
  • Insulator Elements/physiology*
  • Luminescent Proteins/genetics
  • Mutagenesis, Insertional/physiology*
  • Promoter Regions, Genetic/genetics*
  • Transcription Factors/genetics*
  • Transgenes
  • Zebrafish/embryology
  • Zebrafish/genetics*
  • Zebrafish Proteins/genetics*
  • beta-Globins/genetics*
PubMed: 24036575 Full text @ Mol. Genet. Genomics

Genetic lineage tracing and conditional mutagenesis are developmental genetics techniques reliant on precise tissue-specific expression of transgenes. In the mouse, high specificity is usually achieved by inserting the transgene into the locus of interest through homologous recombination in embryonic stem cells. In the zebrafish, DNA containing the transgenic construct is randomly integrated into the genome, usually through transposon-mediated transgenesis. Expression of such transgenes is affected by regulatory features surrounding the integration site from general accessibility of chromatin to tissue-specific enhancers. We tested if the 1.2 kb cHS4 insulators derived from the chicken β-globin locus can shield a transgene from chromosomal position effects in the zebrafish genome. As our test promoters, we used two different-length versions of the zebrafish nkx2.5. We found that flanking a transgenic construct by cHS4 insulation sequences leads to overall increase in the expression of nkx2.5:mRFP. However, we also observed a very high degree of variability of mRFP expression, indicating that cHS4 insulators fail to protect nkx2.5:mRFP from falling under the control of enhancers in the vicinity of integration site.