Genomic organization of AtCBL genes. Aliquots (5 μg per digestion) of genomic DNA from Arabidopsis plants (Columbia ecotype) were digested with BamHI (lanes 1), BglII (lanes 2), EcoRI (lanes 3), and HindIII (lanes 4). (A) After agarose gel electrophoresis, DNA was blotted onto nylon membranes and hybridized under high-stringency conditions with 32P-labeled probes for AtCBL1, AtCBL2, and AtCBL3, respectively. (B) Low-stringency hybridization was performed using AtCBL1 cDNA as a probe. HindIII-digested phage λ DNA was used to provide molecular size markers.