Induction of karyopherin ?1 expression by indole-3-acetic acid in auxin-treated or overproducing tobacco plants.

ABSTRACT: Macromolecules may transfer between the cytoplasm and the nucleus only through specific gates - the nuclear pore complexes (NPCs). Translocation of nucleic acids and large proteins requires the presence of a nuclear localization signal (NLS) within the transported molecule. This NLS is recognized by a class of soluble transport receptors termed karyopherins ? and beta. We previously characterized the expression pattern of the tomato karyopherin ? 1 (LeKAP?1) promoter in transformed tobacco plants. Expression of LeKAP?1 was mainly observed in growing tissues where cell division and extension is rapid. The expression pattern of LeKAP?1 resembled that of auxin-responsive genes. This led us to suggest that auxin participates in the regulation of LeKAP?1 expression. Here we characterized the correlation between auxin level and the activity of the LeKAP?1 promoter. To this end, transgenic tobacco plants carrying the GUS reporter gene under the control of the LeKAP?1 promoter were treated with various levels of exogenous auxin. We also studied transgenic plants in which we increased the endogenous levels of auxin. For this, we expressed in plants both the LeKAP?1 promoter-GUS reporter and the Agrobacterium tumefaciens iaaM gene, which increases the endogenous levels of auxin. The results indicate that the auxin indole-3-acetic acid (IAA) can induce LeKAP?1 expression. We also identified that the sites and levels of LeKAP?1 expression correlated with the endogenous pathways of polar auxin transport.

SUBMITTER: Rand K 

PROVIDER: S-EPMC3218478 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature