Arabidopsis FHY3 and FAR1 Regulate Light-Induced myo-Inositol Biosynthesis and Oxidative Stress Responses by Transcriptional Activation of MIPS1

myo-lnositol-l-phosphate synthase （MIPS） catalyzes the limiting step of inositol biosynthesis and has crucial roles in plant growth and development. In response to stress, the transcription of MIPS1 is induced and the biosynthesis of inositol or inositol derivatives is promoted by unknown mechanisms. Here, we found that the light signaling protein FAR-RED ELONGATED HYPOCOTYL3 （FHY3） and its homolog FAR- RED IMPAIRED RESPONSE1 （FAR1） regulate light-induced inositol biosynthesis and oxidative stress re- sponses by activating the transcription of MIPS1. Disruption of FHY3 and FAR1 caused light-induced cell death after dark-light transition, precocious leaf senescence, and increased sensitivity to oxidative stress. Reduction of salicylic acid （SA） accumulation by overexpression of SALICYLIC ACID 3-HYDROXYLASE largely suppressed the cell death phenotype of fhy3 far1 mutant plants, suggesting that FHY3- and FARl-mediated cell death is dependent on SA. Furthermore, comparative analysis of chromatin immuno- precipitation sequencing and microarray results revealed that FHY3 and FAR1 directly target both MIPS1 and MIPS2. The fhy3 far1 mutant plants showed severely decreased MIPS1/2 transcript levels and reduced inositol levels. Conversely, constitutive expression of MIPSl partially rescued the inositol contents, caused reduced transcript levels of SA-biosynthesis genes, and prevented oxidative stress in fhy3 far1. Taken together, our results indicate that the light signaling proteins FHY3 and FAR1 directly bind the promoter of MIPS1 to activate its expression and thereby promote inositol biosynthesis to prevent light-induced oxidative stress and SA-dependent cell death.

Minimal residual disease-directed immunotherapy for high-risk myelodysplastic syndrome after allogeneic hematopoietic stem cell transplantation

The efficacy of minimal residual disease (MRD)-directed immunotherapy,including interferon-α (IFN-α) treatment and chemotherapy plus granulocyte colony-stimulating factor-primed donor leukocyte infusion (chemo-DLI),was investigated in patients with high-risk myelodysplastic syndrome (MDS) who were MRD-positive after allogeneic hematopoietic stem cell transplantation (allo-HSCT).High-risk MDS patients who received non-T-cell-depleted allo-HSCT at the Peking University Institute of Hematology and were MRD-positive after ailo-HSCT were studied (n =47).The MRD-positive status was considered if leukemia-associated aberrant immune phenotypes or Wilms' tumor gene 1 expression is present in a single bone marrow sample.The cumulative incidence of the relapse and non-relapse mortality 2 years after immunotherapy were 14.5% and 21.4% (P=0.377)and 9.1% and 0.0% (P=0.985) for patients in the IFN-α and chemo-DLI groups,respectively.The probability of disease-free and overall survival 2 years after immunotherapy were 76.4% and 78.6% (P =0.891) and 84.3% and 84.6% (P=0.972) for patients in the IFN-α and chemo-DLI groups,respectively.Persistent MRD after immunotherapy was associated with poor survival.Thus,the MRD-directed immunotherapy was effective for patients with high-risk MDS who were MRD-positive after alIo-HSCT,and the efficacy was comparable between chemo-DLI and IFN-α treatment.