Figure 1.
Production and Screening of Antisense Transformants with Decreased Expression of TK.
(A) Tobacco (N.t.) was transformed with a construct containing the partial length cDNA TK-26 under the control of the constitutive 35S promotor. OCS, octapine synthase.
(B) T2 progeny were grown on sand on 12 mM nitrate in a greenhouse with 170 μmol m−2 sec−1 supplementary light, and the youngest fully expanded leaves of 8-week-old plants were harvested and analyzed for TK transcript and TK activity. Segregation of TK activity in the T2 generation is shown for TK-8. WT, wild type. Each RNA gel blot and the corresponding activity are for an individual segregant.
(C) TK activity in each transformant was related to the activity in wild-type plants of the same age (white bars) and in younger wild-type plants of the same size as the transformant (dark bars) to ensure that plant size–dependent changes in expression did not complicate the quantification of the inhibition of TK expression. WT, wild type.