Overexpression of human erythropoietin (EPO) affects plant morphologies: retarded vegetative growth in tobacco and male sterility in tobacco and Arabidopsis.

Erythropoietin (EPO) is a glycoprotein used for curing human anemia by regulating the differentiation of erythroid progenitors and the production of red blood cells. To examine the expression of recombinant EPO in plants, pPEV-EP21, in which human epo cDNA under the control of the CaMV 35S promoter, was introduced into tobacco and Arabidopsis via Agrobacterium tumefaciens-mediated transformation. The RNA expression level of epo in the transgenic lines was initially estimated by Northern blot analysis. Two transgenic lines, which exhibited a high expression level of epo mRNA determined by Northern analysis, were chosen for Western blot analysis to examine the production of EPO proteins. Those two lines, EP21-12 and EP21-14, revealed detectable bands on the immunoblot. Interestingly, constitutive expression of the human epo gene affected the morphologies in transgenic plants such that vegetative growth of transgenic tobacco was retarded, and male sterility was induced in transgenic tobacco and Arabidopsis.

Expression of the bovine growth hormone alters the root morphology in transgenic tobacco plants.

The bovine growth hormone (bGH) is a natural peptide hormone that controls the differentiation, growth and metabolism, and is produced in the pituitary gland of cows. For the production of bGH from plants, two different bgh clones, of which the pGAbGH1 contaions only mature peptide sequences and the pGAbGH15 contains signal sequences and the first intron, as well as mature peptide sequences, were used. Those bghs under the control of the CaMV 35S promoter and NOS terminator were introduced to tobacco plants via Agrobacterium tumefaciens-mediated transformation. By PCR analyses using bgh and nptII specific primers, 17 and 21 putative transformants were respectively selected from pGAbGH1- and pGAbGH15-transformed tobacco plants. Northern blot analysis showed that the most of the transgenic lines expressed the bgh mRNA. Western blot analysis revealed that the pGAbGH1-transformed tobaccos produced recombinant bGH, but pGAbGH15-transformed ones did not produce the protein. Interestingly, some morphological changes were observed in the roots of transgenic tobacco plants. The transgenic tobacco plants had thick and short roots containing few root hairs in contrast to the non-transformed wild type plants.