IDENTIFICATION AND CLONING OF S-ADENOSYLMETHIONINE DECARBOXYLASE (SAMDC) GENE FROM DICTYOSTELIUM DISCOIDEUM.

Polyamines are aliphatic polycations involved in cellular processes like growth, differentiation, macromolecular biosynthesis, cell death, cell cycle regulation and embryonic development. Intracellular polyamines pools are maintained by de novo synthesis and transport of polyamines from the extracellular milieu. We have exploited the model organism, Dictyostelium discoideum to understand the role of various polyamines during growth and development. In our earlier publication1, we have identified and expressed ornithine decarboxylase (odc) gene from D. discoideum and found putrescine to be more important for growth but not development. On the other hand, we also found the importance of spermidine during development but not during growth. Keeping this in view we have presently identified, cloned and expressed the S-adenosylmethionine decarboxylase (samdc) gene, which is important for the synthesis of spermidine. We measured the various polyamine levels in isolated prestalk and prespore cells collected from migrating slugs. We have analysed the mRNA expression of samdc gene in the wild type cells, odc overexpressing cells and exogenous putrescine treated wild type cells during development