Preparation of Arabidopsis Chloroplasts

INTRODUCTIONThe functions of most Arabidopsis genes cannot be understood simply by studying the expression patterns of their mRNAs. The level of a protein may not be closely correlated with the level of the corresponding mRNA, or a protein may need to be modified to be active. Furthermore, the function of proteins often depends on specific subcellular localization, so knowledge of this can exclude some hypotheses about possible function. For example, if a protein is found exclusively in the cytoplasm, it is unlikely to function as a transcription factor. It is therefore often desirable to prepare subcellular fractions, either to localize proteins or to improve the sensitivity of protein detection. This procedure describes the enrichment of chloroplasts from Arabidopsis.