In ran1-4 the T-DNA is inserted in the second intron of
RAN1, nine bases downstream of the intron splice site (Fig.
4 a). Because of the location and size (6.8 kb) of the T-DNA in- sert in ran1-4, it is likely that splicing and translation of the RAN1 message is disrupted in this mutant. ran1-4 was identi- fied concurrently with other mutant alleles of RAN1 (ran1-1, ran1-2 (Hirayama et al. 1999) and ran1-3 (Woeste and Kieber
2000)). Like ran1-3, the strongest RAN1 mutant allele describ- ed thus far, ran1-4 displays inhibition of cell expansion (Fig.
4 b), constitutive activation of the ethylene-signaling pathway (data not