Regulation of the cell cycle during diapause

Abstract

Insect diapause provides an engaging model for exploring the intricate interplay between signal transduction, gene expression, protein processing, and behavior. At the level of the whole organism, development is halted for several months until environmental or genetic cues terminate diapause and trigger progressive development. In at least three insect species, cell proliferation is arrested during diapause. However, the cell cycle phase of the arrest appears to be species-specific. Brain cells from the flesh fly, Sarcophaga crassipalpis, enter a G1 cell cycle arrest during diapause, while the optic lobe cells of the tobacco hornworm, Manduca sexta, and embryonic cells from the silkworm, Bombyx mori, arrest in the G2 phase of the cell cycle. Hormonal activity is linked to cell cycle status throughout the diapause program. This chapter reviews recent literature in eukaryotic cell cycle regulation, cell cycle control during insect diapause, and cell cycle regulation during dormancy periods in non-insect eukaryotes. Defining the mechanism of cell cycle control during diapause would be of potential benefit for insect control and could yield significant results in the fields of eukaryotic signal transduction, differential gene expression, and protein processing.