Figure 5. Spt is maternally provided, while Sry-α is zygotically expressed in a pulse for cellularization.

(A) RT-PCR and (B) Western blots show Sry-α and Spt expression profiles. Developmental stages are (1) mitotic cycles 1–9; (2) mitotic cycles 10–11; (3) mitotic cycles 11–13; (4) cellularization (shaded); (5) ventral furrow formation; (6) segment formation. Profiles were obtained from three independent RT-PCR or Western Blotting experiments (mean ± s.e.m.).