Cyclin D genes regulate the cell cycle, growth and differentiation in response to intercellular signaling. While the promoters of vertebrate cyclin D genes have been analyzed, the cis-regulatory sequences across an entire cyclin D locus have not. Doing so would increase understanding of how cyclin D genes respond to the regulatory states established by developmental gene regulatory networks, linking cell cycle and growth control to the ontogenetic program. Therefore, we conducted a cis-regulatory analysis on the cyclin D gene, SpcycD, of the sea urchin, Strongylocentrotus purpuratus, during embryogenesis, identifying upstream and intronic sequences, located within six defined regions bearing one or more cis-regulatory modules each. (C) 2013 Elsevier Inc. All rights reserved.