ZmMCM6 protein is excluded from the nucleus in epidermal onion cells. Onion cells were transiently transformed with a UBIp:ZmMCM6-GFP construct and analyzed using epifluorescence (A and C) and light microscopy (B and D). A, Top view of a nucleus showing accumulation of chimeric protein in cytoplasm around the nucleus. The arrows point toward cytoplasm surrounding the nucleus and a transvacuolar cytoplasmic strand. B, Light microscopic image of A. C, Side view of a nucleus showing accumulation of chimeric protein in cytoplasm around the nucleus (arrows), but not inside the nucleus. D, Light microscopic image of C. E, Epifluorescence of an onion epidermal cell bombarded with a 35Sp:Lc-GFP construct encoding the N-terminal 388 amino acids (including the NLS) of a maize transcriptional regulator of anthocyanin biosynthesis in maize (GenBank accession no. A41388) fused with GFP. Most of the fluorescence was detected within the nucleus (arrow). Accumulation of the chimeric protein in cytoplasm around the nucleus, as in A and C, was never observed. Arrowheads in A to D point toward nucleoli.