1. The plant Golgi apparatus is a dynamic organelle
Until the advent of fluorescent protein technology it had proved impossible to image the plant Golgi apparatus in living cells. It therefore came somewhat as a surprise, when using a viral expression system in Nicotiana leaves, that the individual Golgi stacks, expressing a construct of green fluorescent protein (GFP) fused to the carboxy-terminus of the signal anchor sequence of a rat sialyl transferase (ST-GFP), were observed to be mobile within the cortical cytoplasm of the pavement epidermal cells. What was even more surprising was that, using a construct that labelled both the ER and Golgi (AtERD2- GFP – the plant HDEL receptor homologue spliced to GFP), it was noticed that the Golgi was motile over the tubules of the cortical ER network (Fig. 2b; Boevink et al., 1998). This movement was shown to be actin-based and this gave rise to the term ‘stacks on tracks’ describing the Golgi; presumably driven by a myosin motor, travelling over an actin ‘railway track’ which was also overlaid by the ER network. Subsequently the movement of the plant Golgi was confirmed in BY2 cells expressing a plant mannosidase-GFP construct (Nebenführ et al., 1999). Such movement of the Golgi bodies over the cortical ER network is distinct from the rapid movement of the organelle observed in streaming transvacuolar strands of cytoplasm. Direct imaging of Golgi apparently moving on the actin network was observed by the dual expression of ST-GFP and an actin targeted construct consisting of the actin-binding domain of a mouse talin spliced to the yellow fluorescent protein (YFP, Fig. 3; Brandizzi et al., 2002b). Movement of the Golgi has been observed in other tissues such as hypocotyls, petals and root hairs (C. Hawes et al. unpublished), although it is too early to say whether this is a general phenomenon for all cell types (Hawes et al., 2003).
1.โรงงานกอลจิคอมเพล็กซ์เป็นออร์แกเนลล์ที่แบบไดนามิกUntil the advent of fluorescent protein technology it had proved impossible to image the plant Golgi apparatus in living cells. It therefore came somewhat as a surprise, when using a viral expression system in Nicotiana leaves, that the individual Golgi stacks, expressing a construct of green fluorescent protein (GFP) fused to the carboxy-terminus of the signal anchor sequence of a rat sialyl transferase (ST-GFP), were observed to be mobile within the cortical cytoplasm of the pavement epidermal cells. What was even more surprising was that, using a construct that labelled both the ER and Golgi (AtERD2- GFP – the plant HDEL receptor homologue spliced to GFP), it was noticed that the Golgi was motile over the tubules of the cortical ER network (Fig. 2b; Boevink et al., 1998). This movement was shown to be actin-based and this gave rise to the term ‘stacks on tracks’ describing the Golgi; presumably driven by a myosin motor, travelling over an actin ‘railway track’ which was also overlaid by the ER network. Subsequently the movement of the plant Golgi was confirmed in BY2 cells expressing a plant mannosidase-GFP construct (Nebenführ et al., 1999). Such movement of the Golgi bodies over the cortical ER network is distinct from the rapid movement of the organelle observed in streaming transvacuolar strands of cytoplasm. Direct imaging of Golgi apparently moving on the actin network was observed by the dual expression of ST-GFP and an actin targeted construct consisting of the actin-binding domain of a mouse talin spliced to the yellow fluorescent protein (YFP, Fig. 3; Brandizzi et al., 2002b). Movement of the Golgi has been observed in other tissues such as hypocotyls, petals and root hairs (C. Hawes et al. unpublished), although it is too early to say whether this is a general phenomenon for all cell types (Hawes et al., 2003).
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