FUNCTIONAL CHARACTERIZATION OF SPERMINE FAMILY TRANSPORTER caf5(+) IN Schizosaccharomyces pombe (Lindner)

Abstract

Polyamines are well conserved polycationic molecules that are known to interact with nucleic acids and contribute to multiple functions including cell cycle and stress response. The transport of polyamines in and out of the cell is driven by polyamine transporters that play a significant role in polyamine homeostasis. Schizosaccharomyces pombe (Lindner) caf5(+) gene codes for a spermine family transporter that is yet to be characterized functionally. This study aims to understand the contribution of caf5(+) on different processes previously associated with polyamines, by reverse genetics. Deletion mutants of caf5(+), which are viable in normal conditions, were scanned for multiple cellular processes. The results showed that caf5(+) deletion caused shorter cell length and slightly faster growth rate at the optimum conditions. caf5. cells also showed sensitivity to high doses of UV irradiation, while no sensitivity was observed against osmotic stress or another DNA damaging agent hydroxyurea. The mutants could successfully go through different phases of mitosis and meiosis as observed by DNA and septum staining. In summary, caf5(+) gene is involved in normal growth and cell cycle progression, as well as stress response upon UV irradiation.