Proceedings of the XLVI Italian Society of Agricultural Genetics - SIGA Annual Congress

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Poster Abstract - 3.38

STUDY OF PISSA;CYC A3;1 PROMOTER EXPRESSION IN A HETEROLOGOUS SYSTEM

GHIANI A.*, CRIPPA F.**, ONELLI E.***, CITTERIO S.**, AINA R.**, SGORBATI S.**

*) Dipartimento di Produzione Vegetale , Università degli Studi Milano,Via Caloria 2, 20133 Milano, Italy

**) Dipartimento di Scienze dell’Ambiente e del Territorio, Università degli Studi di Milano, Bicocca, P.zza della Scienza 1, 20126 Milano, Italia

***) Dipartimento di Biologia, Università di Milano, Via Celoria 26, 20133 Milano, Italia

cell cycle, cyclin, promoter

In all eukaryotes cell proliferation requires the accurate coordination of the timing and the order of cell cycle events. Consequently, a number of biochemical pathways, called checkpoints, have evolved to ensure that the initiation of particular programmes is dependent upon the successful completion of others, thereby coordinating cell cycle transitions. The cell cycle transitions are controlled by extracellular and intracellular signals that ultimately change the activity of cyclin-dependent kinases (Cdks). The kinase activity of CDKs is dependent on the binding of positive regulators known as cyclins since their cyclical pattern of accumulation and destruction during synchronous divisions. Specific cyclin-CDK complexes regulate particular cell cycle events. Regarding regulatory subunity, to date several genes encoding putative cyclins have been isolated from many plants.

In the past, one cyclin cDNA clones, Pissa;CycA3;1 from Pisum sativum L was isolated by our group. Its characterization showed a differential cyclin expression in different pea organs and a direct relation between Pissa;CycA3;1 and cell proliferation. In addition, using genome walker technique, the 5’ extremity and the promoter were recovered. In order to study its activity during plant development, we introduced this promoter sequence in A. thaliana by floral dip transformation technique. We monitored the promoter activation following the mgfp 5ER (kindly provided by K.R. Siemering) expression through a fluorescence microscopy at different development plant stages. The information that this study can provide are important because in plants the cells cannot move and the morphology and position of organs are determined only by cell division and expansion. The first results show that during development the Pissa;Cyc A3;1cyclin is expressed in proliferating cells of root and shoot meristems and in non-diving cells which retain a measure of totipotence that allows them to dedifferentiate and acquire new function.