Synthesis and mobilization of flagellar glycoproteins during regeneration in Euglena.

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Abstract
Flagellar glycoprotein synthesis and mobilization of flagellar glycoprotein pools were followed during flagellar regeneration in Euglena. The glycosylation inhibitor tunicamycin has little effect on either regeneration kinetics or the complement of flagellar peptides as seen in SDS [sodium dodecyl sulfate] acrylamide gels, but tunicamycin totally inhibits incorporation of exogenously supplied [14C]xylose into flagellar glycoproteins. Deflagellated cells pulsed with tunicamycin for .gtoreq. 30 min, regenerated for 180 min and then redeflagellated are completely or partially inhibited from undergoing a 2nd regeneration even when tunicamycin is no longer present. Euglena apparently retains sufficient glycoprotein pool for 1 complete flagellar assembly. Some of this pool is present on the cell surface since [125I]-labeled surface peptides can be chased into the regenerating flagellum. Glycosylation may also be taking place in the flagellum directly because [14C]xylose was found in 3 flagellar fractions: glycoprotein and 2 others, which are lipophilic and have properties similar to those described for lipid-carrier glycoprotein intermediates in other systems. Pulse-chase experiments also suggest a precursor-product relationship between the presumptive lipid carriers and flagellar glycoproteins. From these results a model is postulated in which Euglena is visualized as retaining sufficient pool of glycoprotein for one complete flagellar regeneration, but the pool is normally supplemented by active xylosylation in situ during regeneration.