A CRY2(PHR) tag has been inserted at the N-terminal end of the endogenous zld locus. This results in a protein that can be rapidly inactivated by blue light illumination; this is not due to protein degradation as the level of protein is not altered after blue-light exposure, but chromatin occupancy is dramatically after blue-light exposure, presumably due to a change in protein conformation.
Embryos laid by zldCRY2 homozygous females fail to gastrulate when laid and raised under blue light compared to controls.
zldCRY2 embryos exhibit nuclear fallout and fail to gastrulate when exposed to blue light from nuclear cycle (NC) 10 to 14 compared to controls.
zldCRY2 embryos exposed to blue light starting at entry into either NC13 or NC14 exhibit gastrulation defects when compared to controls.
zldCRY2 embryos exposed to blue light during minor wave of zygotic genome activation (starting at NC10 until beginning of NC13) fail to gastrulate compared to controls.
