Molecular cloning and characterization of a novel pollen predominantly membrane protein gene BcMF12 from Brassica campestris ssp. chinensis.

A novel membrane protein gene, BcMF12, was isolated from Chinese cabbage (Brassica campestris L. ssp. chinensis Makino) using rapid amplification of the cDNA ends based on a pollen-specific cDNA fragment (DN237936). The cDNA was 1,155 bp in length with an open reading frame of 894 bp capable of encoding a putative polypeptide of 297 amino acids with an estimated molecular mass of 34.6 kDa and a predicted isoelectric point of 9.6. Comparative and bioinformatics analyses revealed that BcMF12 showed high similarities with some membrane protein sequences previously published in the public database and contained six highly conserved transmembrane domains corresponding to six highly hydrophobic regions. This indicates that BcMF12 may be a putative membrane protein. RNA gel blot analysis indicated that the transcripts of BcMF12 were abundant in the flower bud, flower and anther, but not detected in the root, stem, leaf and pistil. Moreover, the BcMF12 transcripts were detectable at the late stages of pollen development. Morphological investigations of pollen from the BcMF12 antisense transgenic plants showed that most of pollen grains of transgenic plants were abnormal. These results strongly suggest that BcMF12 is a novel pollen-preferentially membrane protein which play an important role during the pollen development in Chinese cabbage.