Woltjen Lab

Stem Cells and Genome Engineering


In and Around the Lab


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Representative images of human iPS cell colonies expressing one of three reporter genes (from left to right): lacZ (blue), GFP (green) and mCherry (red).

Gosho Sakura

Cherry blossoms (Sakura) in the gardens at the Imperial Palace (Gosho), Kyoto, April 2010.
photo: Knut Woltjen

PB-iPCS Twins

The first mouse piggyBac iPS cell colonies. Twins born April 13, 2008. Congratulations! Welcome Mia and Tia to the world.
photo: Knut Woltjen



piggyBac iPS cell-derived 10.5dpc chimeric mouse embryo. Transgene expression induced in utero to activate factor-linked lacZ (blue).
First appeared in Woltjen et al. (2009) Nature 458, p766-770.
photo: Knut Woltjen


Trichoplusia ni

Trichoplusia ni – the Cabbage Looper Moth
Within this moth’s genome is where piggyBac was discovered by Malcolm J Fraser.
photo: Pedro Pires [permission for photo reproduction]
Check out the amazing world of butterflies and moths at:http://www.lusoborboletas.org


Nature Cover Fail!

Submission for the cover of Nature (rejected! Doh.), depicting (rather loosely) the application of piggyBac transposons for iPS cell production.
Adobe Illustrator Drawing: Knut Woltjen