Fig. 2.

CDK expression levels during maize endosperm development. a CDK and actin RNA levels during endosperm development. RT-PCR was performed on total RNA isolated from endosperm at different developmental stages (indicated by DAP) with CDK- or ACT1-specific primers. Reaction products were separated by electrophoresis and exposed to a Phosphorscreen. b CDK RNA levels relative to actin RNA in developing endosperms. Signal from amplicons from two independent experiments was quantified and expression was normalized relative to 7 DAP, which is considered one expression unit. Error bars show standard error of the means. c Immunoblot analysis of CDKs present during maize endosperm development. Total soluble protein extracted from endosperm at different developmental stages (indicated by DAP) was separated by SDS-PAGE and immunoblotted with affinity-purified antibodies as indicated on the right. An immunoblot with actin antibody is shown as the loading control