Stable germline transgenesis using theMinosTc1/marinerelement in the sea urchin,Lytechinus pictus

Abstract

Stable transgenesis is a transformative tool in model organism biology. While the sea urchin is one of the oldest animal models in cell and developmental biology, it has relied on transient manipulations of wild animals, and has lacked a strategy for stable transgenesis. Here we build on recent progress to develop a more genetically tractable sea urchin species, Lytechinus pictus, to establish a robust transgene integration method. Three commonly used transposons (Minos, Tol2, piggyBac) were tested for non-autonomous transposition, using plasmids containing a polyubiquitin promoter upstream of a H2B-mCerulean nuclear marker. Minos was the only transposable element that resulted in significant expression past metamorphosis. F0 animals were raised to sexual maturity and spawned to determine germline integration, transgene inheritance frequency, and to characterize expression patterns of the transgene in F1 progeny. The results demonstrated transgene transmission through the germline, the first example of a germline transgenic sea urchin, and indeed of any echinoderm. This milestone paves the way for the generation of diverse transgenic resources that will dramatically enhance the utility, reproducibility, and efficiency of sea urchin research.