A subgroup of MYB transcription factor genes undergoes highly conserved alternative splicing in Arabidopsis and rice.
MYB transcription factor genes play important roles in many developmental processes and in various defence responses of plants. Two Arabidopsis R2R3-type MYB genes, AtMYB59 and AtMYB48, were found to undergo similar alternative splicing. Both genes have four distinctively spliced transcripts that encode either MYB-related proteins or R2R3-MYB proteins. An extensive BLAST search of the GenBank database resulted in finding and cloning two rice homologues, both of which were also found to share a similar alternative splicing pattern. In a semi-quantitative study, the expression of one splice variant of AtMYB59 was found to be differentially regulated in treatments with different phytohormones and stresses. GFP fusion protein analysis revealed that both of the two predicted nuclear localization signals (NLSs) in the R3 domain are required for localizing to the nucleus. Promoter-GUS analysis in transgenic plants showed that 5'-UTR is sufficient for the translation initiation of type 3 transcripts (encoding R2R3-MYB proteins), but not for type 2 transcripts (encoding MYB-related proteins). Moreover, a new type of non-canonical intron, with the same nucleotide repeats at the 5' and 3' splice sites, was identified. Thirty-eight Arabidopsis and rice genes were found to have this type of non-canonical intron, most of which undergo alternative splicing. These data suggest that this subgroup of transcription factor genes may be involved in multiple biological processes and may be transcriptionally regulated by alternative splicing.
Peking-Yale Joint Center for Plant Molecular Genetics and Agro-Biotechnology, National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, PR China.
Jigang
J
Li
Xiaojuan
X
Li
Lei
L
Guo
Feng
F
Lu
Xiaojie
X
Feng
Kun
K
He
Liping
L
Wei
Zhangliang
Z
Chen
Li-Jia
LJ
Qu
Hongya
H
Gu
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins; D015870:Gene Expression; D020570:Genes, myb; D007438:Introns; D008969:Molecular Sequence Data; D019913:Nuclear Localization Signals; D019697:Onions; D012275:Oryza / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics*; D020598:Proto-Oncogene Proteins c-myb / Q000235:genetics*; D022821:RNA Splice Sites; D017385:Sequence Homology; D020506:Untranslated Regions
C511988:ATR1 protein, Arabidopsis; D029681:Arabidopsis Proteins; C511989:CPC protein, Arabidopsis; D019913:Nuclear Localization Signals; D010940:Plant Proteins; D020598:Proto-Oncogene Proteins c-myb; D022821:RNA Splice Sites; D020506:Untranslated Regions