The CAPRICE ( CPC)-like MYB gene family encodes R3-type MYB transcription factors in Arabidopsis. There are six additional CPC-like MYB sequences in the Arabidopsis genome, including TRYPTICHON ( TRY), ENHANCER OF TRY AND CPC1 and 2 ( ETC1 and ETC2), ENHANCER OF TRY AND CPC3/CPC-LIKE MYB3 ( ETC3/CPL3), and TRICHOMELESS1 and 2 ( TCL1 and TCL2). We independently identified CPC-LIKE MYB4 ( CPL4), which was found to be identical to TCL2. RT-PCR analysis showed that CPL4 is strongly expressed in shoots, including true leaves, but not in roots. Promoter-GUS analyses indicated that CPL4 is specifically expressed in leaf blades. Although CPC expression was repressed in 35S:: ETC1, 35S:: ETC2 and 35S:: CPL3 backgrounds, CPL4 expression was not affected by ETC1, ETC2 or CPL3 over-expression. Notably, several chimeric transcripts may result from inter-genic alternative splicing of CPL4 and ETC2, two tandemly repeated genes on chromosome II. At least two chimeric transcripts named CPL4-α and CPL4-β are expected to encode complete CPC-like MYB proteins.
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