Selective induction of a giant puff in Drosophila hydei by vitamin B6 and derivatives

Vitamin B₆ induces in vivo as well as in vitro the appearance of a puff at region 2–48C in Drosophila hydei. At concentrations of 10^–2 M or lower, region 2–48C is the only region responding to vitamin B₆ provided that oligomycin is present in the incubation medium. Pyridoxal phosphate and pyridoxamine phosphate supplied to medium containing oligomycin induce upon incubation of salivary glands a larger puff at 2–48C. — Puff 2–48C produces large quantities of a unique RNP-product; globular 140–220 Å particles which aggregate to stable complexes of 0.1–0.2 in diameter. Upon continuous in vitro incubation with vitamin B₆, puff 2–48C becomes loaded with these aggregates which have never been observed in any other puff of Drosophila hydei.