Reverse Genetics and Functional Complementation Experiments Unveil a Unique Nucleobase Cation Symporter AtNCS1 in Arabidopsis thaliana

摘要

Locus At5g03555 encodes for the sole nucleobase cation symporter 1(AtNCS1) in the Arabidopsis genome. Independently derived Arabidopsis insertion mutants, AtNcs1-1 and AtNcs1-3, were used for in planta toxic nucleobase analog growth studies and radio-labeled nucleobase uptake assays to characterize solute transport specificities. These results correlate with similar growth and uptake studies of AtNCS1 expressed in Saccharomyces cerevisiae. Both in planta and heterologous expression studies in yeast revealed a unique solute transport profile for AtNCS1 in moving adenine, guanine and uracil. This is in stark contrast to the canonical transport profiles determined for the well-characterized S. cerevisiae NCS proteins FUR4 (uracil transport) or FCY2 (adenine, guanine, and cytosine transport).