I got a request to post the antisense references I received, so here are
both of them:
J. Li et al. 1995. Arabdiopsis phosphoribosylanthranilate isomerase:
molecular genetic analysis of triplicate tryptophan pathway genes. Plant
Cell 7, 447-461
H. Xu et al. 1995. Bcp1, a gene required for male fertility in
Arabidopsis. PNAS 92, 2106-2110.