engleski

N-glycoprotein patterns related to morphogenesis in Mammillarica gracillis tissue culture

Many functional proteins in eucaryotes are known to be glycosylated. The elucidation of N-gylcans in plants has raised interest in the past years due to several physiological roles attributed to these structures: correct folding, biological activity and stability of proteins. However, little information about the glycoprotein patterns related to cell differentiation, dedifferentiation and transformation is available. A spontaneous switch from the organised to disorganised way of growth in the Mammillaria gracillis tissue culture makes this system suitable to study plant morphogenesis. Mammillaria gracillis plants develop calli without any exogenous growth regulators. This habituated callus spontaneously regenerates normal and hyperhydric shoots. In order to compare habituated callus with the tumorous one, cactus cells were transformed with Agrobacterium tumefaciens wild strain B6S3 (TW tumour). This tumour line grows vigorously without expression of any morphogenic potential. The aim of this work was to obtain information about changes in N-glycosylation pattern related to specific developmental processes such as growth of habituated callus and the spontaneous regeneration in the callus culture as well as tumour transformation. Proteins were separated by 1-D and 2-D SDS-polyacrylamide gel electrophoresis, transferred to a nitrocellulose membrane and treated with digoxigenin- and biotin-labeled lectins. Composition of N-glycans analysed by MALDI-TOF MS revealed that the majority of the detected oligosaccharides were complex-type. Tumour TW clearly showed more diversity in N-glycans then untrasformed tissues. Obtained results indicate that the complexity of the N-glycan structures increased with the loss of the tissue organisation. The N-glycosylation pattern of soluble cellular proteins can be related to the specific morphogenic level of cactus tissue.

N-glycoprotein; Mammillarica gracillis

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