Catalyzes the C4-hydroxylation of desacetoxyvindoline. 2-oxoglutarate + deacetoxyvindoline + O2 = 4-O-deacetylvindoline + CO2 + succinate Binds 1 Fe(2+) ion per subunit. Alkaloid biosynthesis; vindoline biosynthesis. Monomer. Highest levels in leaves, lower levels in stems and fruits. Not expressed in flowers and roots. By light. Belongs to the iron/ascorbate-dependent oxidoreductase family.