Myb controls G(2)/M progression by inducing cyclin B expression in the Drosophila eye imaginal disc.
The c-myb proto-oncogene product (c-Myb) is a transcriptional activator. Vertebrate c-Myb is a key regulator of the G(1)/S transition in cell cycle, while Drosophila Myb (dMyb) is important for the G(2)/M transition. Here we report that dMyb induces expression of cyclin B, a critical regulator of the G(2)/M transition, in Drosophila eye imaginal disc. In the wild-type eye disc, dmyb mRNA was expressed in the stripes both anterior and posterior to the morphogenetic furrow. Ectopic expression of C-terminal-truncated dMyb in the eye disc caused ectopic expression of cyclin B and the rough eye phenotype. This rough eye phenotype correlated with prolonged M phase, caused by overexpression of cyclin B. Cyclin B expression was lost in dmyb-deficient clones. In Schneider cells, the activity of the cyclin B promoter was dramatically reduced by loss of dMyb using the RNA interference method. Mutations of the multiple AACNG sequences in the cyclin B promoter also abolished the promoter activity. These results indicate that dMyb regulates the G(2)/M transition by inducing cyclin B expression via binding to its promoter.
Okada
Masahiro
M
Laboratory of Molecular Genetics, RIKEN Tsukuba Institute and CREST Research Project of JST (Japan Science and Technology Corporation), 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan.
Akimaru
Hiroshi
H
Hou
De-Xing
DX
Takahashi
Tomomi
T
Ishii
Shunsuke
S
D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D019926:Cyclin B / Q000235:genetics*; D017931:DNA Primers; D004330:Drosophila; D029721:Drosophila Proteins; D005123:Eye / Q000378:metabolism* / Q000648:ultrastructure; D016195:G2 Phase / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology*; D008855:Microscopy, Electron, Scanning; D008938:Mitosis / Q000502:physiology*; D020598:Proto-Oncogene Proteins c-myb / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015533:Transcriptional Activation / Q000502:physiology
C503698:CycB protein, Drosophila; D019926:Cyclin B; D017931:DNA Primers; D029721:Drosophila Proteins; D020598:Proto-Oncogene Proteins c-myb