Preferential up-regulation of G2/M phase-specific genes by overexpression of the hyperactive form of NtmybA2 lacking its negative regulation domain in tobacco BY-2 cells.
Plant Physiol, 2009/4;149(4):1945-57.
Kato K[1], Gális I, Suzuki S, Araki S, Demura T, Criqui MC, Potuschak T, Genschik P, Fukuda H, Matsuoka K, Ito M
Affiliations
PMID: 19244455DOI: 10.1104/pp.109.135582
Impact factor: 8.005
Abstract
Many G2/M phase-specific genes in plants contain mitosis-specific activator (MSA) elements, which act as G2/M phase-specific enhancers and bind with R1R2R3-Myb transcription factors. Here, we examined the genome-wide effects of NtmybA2 overexpression, one of the R1R2R3-Myb transcription factors in tobacco (Nicotiana tabacum). We used a custom-made 16-K cDNA microarray for comparative transcriptome analysis of transgenic tobacco BY-2 cell lines that overexpress NtmybA2 or its truncated hyperactive form. The microarray was also used to determine the transcript profile during the cell cycle in synchronized cultures of BY-2 cells. Combined microarray data from transgenic lines and synchronized cells revealed that overexpression of the truncated hyperactive form of NtmybA2, but not its full-length form, preferentially up-regulated many G2/M phase-specific genes in BY-2 cells. We determined promoter sequences of several such up-regulated genes and showed that all contain MSA-like motifs in the proximal regions of their promoters. One of the up-regulated genes, NtE2C, encoding for cyclin-specific ubiquitin carrier proteins, contained a single functional MSA-like motif, which specifically controlled the expression of a reporter gene in the G2/M phase in BY-2 cells. Furthermore, a genomic footprint experiment showed that the MSA element in the NtE2C promoter interacted with nuclear proteins in vivo. Therefore, we propose that the transcription of many G2/M phase-specific genes in tobacco is positively regulated by NtmybA2, in most cases through direct binding to the MSA elements.
MeSH terms
Base Sequence; Cell Division; DNA Footprinting; G2 Phase; Gene Expression Regulation, Plant; Genes, Plant; Homeostasis; Molecular Sequence Data; Mutant Proteins; Oligonucleotide Array Sequence Analysis; Plant Proteins; Protein Structure, Tertiary; Proto-Oncogene Proteins c-myb; RNA, Messenger; Regulatory Sequences, Nucleic Acid; Sequence Deletion; Nicotiana; Up-Regulation
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