Screening For Genetic Interactors Of Arabidopsis TRANSPORTIN 1

TRANSPORTIN 1(TRN1)belongs to Importin ? family,which in model plant Arabidopsis thaliana is composed of 17 members.Its homologs in yeast and mammalian cells are mainly involved in target proteins' nuclear import,therefore to regulate many biological processes.In addition increasing evidence indicate they also function in other ways.For example,Arabidopsis TRN1 regulates microRNAs' activity by promoting ARGONOUTE 1's function,but not by mediating their cytoplamic-nuclear distribution.To search for more TRN1's genetically interacting genes,we first carefully analyzed the phenotypes and allelism of its mutants,and found its function is required for shoot apical meristem(SAM)development and maintenance.Based on these results,we conducted further genetic screening by transgenic activation tagging using a weak allele(sic1),and obtained several enhancers and repressors,among which a repressor B639 was further analyzed.Our data indicate a mutation in KAKTUS(KAK)gene may be responsible for B639's phenotype.To confirm these results,we constructed more double mutants using their independent alleles and their phenotypes support that these two genes genetically interact.The results of this study provide solid genetic evidence that will be definitely helpful for further investigating the underlying molecular mechanisms,in particular,in regulating SAM development.