A Brassica napus skp1-like gene promoter drives GUS expression in Arabidopsis thaliana male and female gametophytes

We isolated a gene, BnSKP1 gamma 1, expressed in rapeseed (Brassica napus) microspores, which encodes a protein closely related to the Saccharomyces c erevisiae Skp1p protein previously shown to play a role in cell cycle regul ation. Twelve SKP1-related genes have already been identified in the Arabid opsis thaliana genome. Using a PCR-based strategy, we isolated three other genes. To date, most data available concerning the function of the SKP1-rel ated genes in plants are indirect. Studies on transgenic A. thaliana plants show that a 1100-bp BnSKP1 gamma 1 promoter fragment can direct GUS expres sion in female gametophytes soon after the first haploid mitosis and in mal e gametophytes from the tetrade stage. No GUS expression can be detected in sporophytic tissues. RT-PCR experiments suggest that this gene is expresse d in a similar way in rapeseed. This is the first reported case of a gene e xhibiting such an expression pattern in angiosperms.