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 cells1[W]

Kiichi Kato, Ivan Galis, Shiori Suzuki, Satoshi Araki, Taku Demura, Marie Claire Criqui, Thomas Potuschak, Pascal Genschik, Hiroo Fukuda, Ken Matsuoka, Masaki Ito

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21 Citations (Scopus)


Many G2/M phase-specific genes in plants contain mitosis-specific activator (MSA) elements, which act as G2/M phasespecific 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.

Original languageEnglish
Pages (from-to)1945-1957
Number of pages13
JournalPlant Physiology
Issue number4
Publication statusPublished - Apr 2009
Externally publishedYes


ASJC Scopus subject areas

  • Plant Science
  • Genetics
  • Physiology

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