Analysis of the Expression of a CycD3 Gene Isolated from Nicotiana tabacum

D-type cyclins (CycD) are thought to control the onset of cell division and responses to extracellular signals during G1 phase. In this study a cyclin D3 (CycD3) gene was isolated from Nicotiana tabacum. Southern blot analysis indicated that it was present in a single-copy in the N. tabacum genome, and Northern analysis showed that it was only expressed in organs and tissues containing dividing cells. Exposure to cold and salt stresses resulted in decreased CycD3 expression supporting the view that its expression is closely related to cell growth.