TI  -   <prot>HOX11</prot>   interacts with protein phosphatases  <prot>PP2A</prot>  and  <prot>PP1</prot>  and disrupts a G2/M
      cell-cycle checkpoint.
PG  - 454-8
AB  - <prot>Hox11</prot> is an orphan homeobox gene that controls the genesis of the spleen.
      <prot>HOX11</prot> is also oncogenic, having been isolated from a chromosomal
      breakpoint in human T-cell leukaemia. Transgenic mice that redirected
      <prot>HOX11</prot> to the thymus demonstrated cell-cycle aberration and progression to
      malignancy. We observed that the protein   <prot>HOX11</prot>   interacted with protein
       <prot><prot>serine-threonine phosphatase 2A</prot> catalytic subunit</prot> (<prot>PP2AC</prot>) , as well as
       <prot>protein phosphatase 1</prot> (<prot>PP1C</prot>)  in mammalian cells. Inhibition of <prot>PP2A</prot> can
      regulate the cell cycle and control the activation of maturation-promoting
      factor in Xenopus oocytes. Microinjection of <prot>HOX11</prot> into Xenopus oocytes
      arrested at the G2 phase of the cell cycle promoted progression to the M
      phase. G2 arrest can be induced by gamma-irradiation, but is eliminated by
      expression of <prot>HOX11</prot> within a T-cell line. Thus   <prot>HOX11</prot>   is a cellular
      oncogene that targets  <prot>PP2A</prot>  and  <prot>PP1</prot> , both of which are targets for
      oncogenic viruses and chemical tumour promoters. This interaction suggests
      a mechanism by which a homeobox can alter the cell cycle.
AD  - Howard Hughes Medical Institute, Washington University School of Medicine,
