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Updated: May 26, 2026
A Rapid Protocol for Integrating Extrachromosomal Arrays With High Transmission Rate into the C. elegans Genome
Published on: December 9, 2013
Single/low-copy integration of transgenes in Caenorhabditis elegans using an ultraviolet trimethylpsoralen method
Eriko Kage-Nakadai1, Hiroyuki Kobuna, Osamu Funatsu
1Department of Physiology, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
Background:
Transgenic strains of Caenorhabditis elegans are typically generated by injecting DNA into the germline to form multi-copy extrachromosomal arrays. These transgenes are semi-stable and their expression is silenced in the germline. Mos1 transposon or microparticle bombardment methods have been developed to create single- or low-copy chromosomal integrated lines. Here we report an alternative method using ultraviolet trimethylpsoralen (UV/TMP) to generate single/low-copy gene integrations.
Results:
We successfully integrated low-copy transgenes from extrachromosomal arrays using positive selection based on temperature sensitivity with a vps-45 rescue fragment and negative selection based on benzimidazole sensitivity with a ben-1 rescue fragment. We confirmed that the integrants express transgenes in the germline. Quantitative PCR revealed that strains generated by this method contain single- or low-copy transgenes. Moreover, positive selection marker genes flanked by LoxP sites were excised by Cre recombinase mRNA microinjection, demonstrating Cre-mediated chromosomal excision for the first time in C. elegans.
Conclusion:
Our UV/TMP integration method, based on familiar extrachromosomal transgenics, provides a useful approach for generating single/low-copy gene integrations.
