| CmPP16(Cucurbita maxima Phloem Protein-16)from Cucurbita maxima is a plant paralog to viral movement protein. There are two homologous proteins named CmPP16-1 (16.5 kD) and CmPP16-2(15.6 kD). CmPP16 can form nuclear ribonuclear protein (RNP) with RNA in a non-sequence specific manner(and also move together with its mRNA, and possess the characteristics that dilate the plasmodesmal microchannels in the course of the cell-to-cell trafficking of RNPs. Thus, CmPP16 may play an important role in developmental progress and long-distance signaling system.We cloned cDNA sequences of CmPP16-1 and CmPP16-2 from"Xiehuatian", a local cultivar of Cucurbita mosechate Duchesne Poir, N, by RT-PCR. After sequencing, the cDNA of CmPP16-2 was inserted into the pET-28a(+) vector to construct recombinant plasmid named pET-28a(+)-CP2。Approximately a 18.6 kD protein fused with 6×His tag was expressed and purified. The fusion protein was injected into BALB/c mice to make polyclonal antibody. The titration of the antibody was determined by ELISA assay and Western hybridization. The antibody was used to investigate system transport of CmPP16 protein in different plant materials."Jizasihao"scions, a local cultivar of cucumber, were grafted onto"Xiehuatian"stocks to study the systemic transportation of CmPP16. Western hybridization showed that there were two bands in the NC membrane of pumpkin materials. While there was a single band in pumpkin×cucumber interspecific hybrid materials and no band in cucumber materials. Our data revealed that both CmPP16-1 and CmPP16-2 could traffic systematically in pumpkin, but only CmPP16-2 could traffic from pumpkin rootstocks to cucumber scion, suggesting that CmPP16-1 and CmPP16-2 could transport in different manners and have different functions in system transport. |
