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

Verona, Italy - 24/27 September, 2003

ISBN 88-900622-4-X

Poster Abstract - 5.48

SEEKING FOR PETUNIA HYBRIDA MIP1 GENE

M. VIVIANI, G.B. TORNIELLI, M. PEZZOTTI

Dip. Scientifico e Tecnologico, Università degli Studi di Verona

mei2, mip1, meiosis

Sexual reproduction is a fundamental way to provide genetic variability and meiosis is one of the most important steps of this process. Since meiosis is highly conserved among eukaryotes, the knowledge acquired in simple organisms, like Schizosaccharomyces pombe, can be used to understand this phenomenon in higher organisms. Yeast mei2 and mip1 genes play a very important role in meiosis. Mei2 protein, in the cytoplasm, is responsible for the synthesis of pre-meiotic DNA, while, in the nucleus, promotes meiosis I. Mip1 protein interacts weakly with Mei2 in the cytoplasm, probably helping Mei2 protein folding, but its biological function may be more complex.

Several sequences with homology to the yeast mei2 and mip1 genes were identified in some higher organisms, among which we recently isolated mei2 (Moretti et al. 1999) from Petunia hybrida.

This study reports the isolation and the molecular characterisation of mip1 from P. hybrida. The isolation of mip1 was carried out by screening a cDNA library of P. hybrida ovaries performing PCR with degenerated primers. These primers were designed on the conserved blocks resulted from the alignment of S. pombe Mip1 protein with seven homologous proteins belonging to other eukaryotes (H. sapiens, M. musculus, D. melanogaster, A. thaliana, C. elengans, S. cerevisiae). The entire sequence, 4467 bp, has been isolated using semi-nested PCR. Tissue specificity was performed on various plant organs of P. hybrida by Real Time RT-PCR. mip1 was highly expressed in the ovary, while it was expressed at basal levels in petals, sepals and stems. There were no detectable levels of mip1 transcripts in the leaves.

In order to investigate the role of mip1 in P. hybrida we will construct silenced mutants of this gene using the RNA-antisense method.