Plant DNA topoisomerases: Structure, function, and cellular roles in plant development

Regulation of the topological state of DNA is critical for cellular viability. DNA topoisomerases alter DNA topology and participate in nearly all events related to DNA metabolism such as replication, transcription, recombination, and chromosome segregation. Despite significant progress in our understanding of the structure, mechanism, and the role of topoisomerases in diverse cellular processes in bacteria, yeast, and animal systems, the roles of plant topoisomerases are poorly understood. In recent years expression studies, characterization of recombinant topoisomerases, and gene knockout studies have highlighted the importance of topoisomerases in plant DNA replication, mitosis, cell proliferation, organelle division, meiotic recombination, morphogenesis, and plant development. We have focused this review specifically on plant topoisomerases, with an emphasis on their biological role in plant development.