DEVELOPMENTAL EXPRESSION AND REGULATION BY LIGHT OF 2 CLOSELY-RELATEDBETA-TUBULIN GENES IN LUPINUS-ALBUS

We present here the characterization of a Lupinus albus beta-tubulin g ene, TubB2, which is closely related to TubBl [22]. Both TubB1 and Tub B2 transcripts are present in the embryonic axis of lupin dry seeds. T he patterns of developmental expression of TubB1 and TubB2 beta-tubuli n genes are strongly correlated. Both genes are expressed at higher le vels in hypocotyls of 7-day-old etiolated plants compared to hypocotyl s from plants grown under light/dark cycles. When etiolated plants are exposed to continuous white light, differential changes in the steady state levels of the TubB1 and TubB2 mRNAs from hypocotyls are observe d. These changes are accompanied by an inhibition of hypocotyl extensi on.