Bcd and Eve profile as determined by immunostaining of embryos in cycle 14 at uniform temperature and in a temperature step.
(A–C) Embryos developed at uniform 23°C. Micrographs show a region of an embryo in interphase with Bcd localized to nuclei (A), in prometaphase/ metaphase with Bcd diffusely associated with nuclei (B), and in metaphase/anaphase with Bcd dissociated from nuclei and associated presumably with the cytoskeleton (C). (D–G) The embryo was exposed to a temperature step with anterior 20°C and posterior 27°C and then removed during cycle 14. Fluorescent micrographs show nuclei (D) and Bcd (E) in embryos developed in a temperature step. The Bcd gradient is abnormal with Bcd localized to nuclei only behind a region of abnormal nuclear morphology. (F) Eve stripes are expressed in the correct positions despite the abnormal Bcd intensity profile and abnormal morphology of nuclei in the cortex of the embryo. (G) Plot of Bcd and Eve normalized intensities as a function of percent egg length.