Clone And Function Analysis Of The Promoter Of Pollen Profilin Gene In Rice

Profilin is an actin monomer binding protein that,depending on the different conditions causes both polymerization and depolymerization of actin filaments. We found rice profilin gene expresses in pollen and anther specially,and presumed it plays a significant role in signal transduction and regulation in the actin reconstruction during pollen germination and pollen tube elongation.The promoter of pollen proflin gene in rice,named PSP-P,was cloned through twice genome walking and fully sequenced. A comparison with the tenth chromosome of rice published in GenBank is shown 96% identity. The results of comparing in the Eukaryotic Promoter Database show that the +2-71 region of the sequence is about 50% similarity to the promoter key sequence of Lycopersicon esculentum pollen-special gene LAT52 and Helianthus annuus anther-special gene SF2.This promoter including three TATA boxes,three CAAT boxes and two G-boxes and a lot of other cis-acting elements,which suggests this promoter,regulate theexpression of profilin gene temporally and spatially.In order to identify important promoter elements controlling the profilin gene,three of 5' promoter deletions were fused to the GUS reporter gene,which named PSP-P1,PSP-P2 and PSP-P3. These recombination vectors were then introduced into different flowering phases tobacco pollens via Agrobacterium rhizogenes-medialed transient expression. Expression level of the GUS gene of PSP-P3 is very low,only about 5% pollens were stained,that of PSP-P2 is much higher,about 80% pollens were dark blue. GUS gene of PSP-P1 can't express in the pollen. GUS gene in PSP-P2 can express in mature pollen and pollen tubes.