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Mediator is a conserved transcriptional co-activator that links transcription factors bound at enhancer elements to RNA Polymerase II. Mediator-RNA Polymerase II interactions can be sterically hindered by the Cyclin Dependent Kinase 8 (CDK8) module, a submodule of Mediator that acts to repress transcription in response to discrete cellular and environmental cues. The CDK8 module is conserved in all eukaryotes and consists of 4 proteins: CDK8, CYCLIN C (CYCC), MED12, and MED13. In this study, we have characterized the CDK8 module of Mediator in maize. The maize genome contains single copy genes forCdk8, CycC,andMed13,and two genes forMed12.Analysis of expression data for the CDK8 module demonstrated that all five genes are broadly expressed in maize tissues, withZmMed12a, ZmMed12b,andZmMed13exhibiting similar expression patterns. We performed aDissociation (Ds)insertional mutagenesis, recovering two independent insertions in theZmMed12agene. One of theseDsinsertions results in a truncation of theZmMed12atranscript. Our molecular characterization of the maize CDK8 module, as well as transposon tagging ofZmMed12a,establish the basis for molecular and functional studies of these important transcriptional regulators inZea mays.