Project description:The experimental design was to determine the regulon of the transcriptional activator RarA. This was done by comparing the transcriptome profiles between a rarA overexpressor and the baseline control. RarA overexpression was achieved by plasmid mediated overexpression of the rarA gene and the baseline control was a vector only strain.
Project description:RARA haploinsufficiency is an invariable consequence of t(15;17) reciprocal translocations in acute promyelocytic leukemia (APL). Furthermore, retinoids and RARA activity have been implicated in hematopoietic self-renewal, lineage commitment and neutrophil maturation. We and others therefore predicted that RARA haploinsufficiency would contribute to APL pathogenesis. To test this hypothesis we crossed RARA+/- mice with mice expressing PML-RARA from the Cathepsin G locus (mCG-PR). We found that RARA haploinsufficiency cooperated with PML-RARA, only modestly influencing the pre-leukemic and leukemic phenotype. Bone marrow from mCG-PR+/- x RARA+/- mice had decreased numbers of mature myeloid cells, increased ex vivo myeloid cell proliferation and an increased competitive advantage following transplantation. RARA haploinsufficiency did not alter mCG-PR dependent leukemic latency or penetrance, but did influence the distribution of leukemic cells; mCG-PR+/- x RARA+/- mice presented more commonly with low to normal white blood cell counts and with myeloid infiltration of lymph nodes. APL arising in these mice was responsive to ATRA, and had virtually no differences in expression profiling compared to tumors arising in mCG-PR+/- x RARA+/+ mice. These phenotypes were dependent on PML-RARA activity, since they were not detected in RARA+/- mice in the absence of the mCG-PR transgene. These data show that RARA haploinsufficiency (like PML haploinsufficiency and RARA-PML) can cooperate with PML-RARA to influence the pathogenesis and phenotype of APL in mice, but that PML-RARA is the driver of t(15;17) APL.
Project description:PML/RARa is of crucial importance in acute promyelocytic leukemia (APL) both pathologically and therapeutically. Using a genome-wide approach, we identified in vivo PML/RARa binding sites in ZnSO4 treated PR9 cells. A total of 2,979 high quality binding sites were identified, representing 1,981 unique RefSeq genes. The supplementary bed file contains all 2,979 high quality PML-RARa binding sites reported in the paper.
Project description:Transcriptional profiling of murine cells expressing PML/RARA at the early promyelocyte stage (4 weeks old, preleukemic) and in full blown PML/RARA leukemia generated by transducing PML/RARA bone marrow with a Flt3-ITD retroviral vector
Project description:RARA haploinsufficiency is an invariable consequence of t(15;17) reciprocal translocations in acute promyelocytic leukemia (APL). Furthermore, retinoids and RARA activity have been implicated in hematopoietic self-renewal, lineage commitment and neutrophil maturation. We and others therefore predicted that RARA haploinsufficiency would contribute to APL pathogenesis. To test this hypothesis we crossed RARA+/- mice with mice expressing PML-RARA from the Cathepsin G locus (mCG-PR). We found that RARA haploinsufficiency cooperated with PML-RARA, only modestly influencing the pre-leukemic and leukemic phenotype. Bone marrow from mCG-PR+/- x RARA+/- mice had decreased numbers of mature myeloid cells, increased ex vivo myeloid cell proliferation and an increased competitive advantage following transplantation. RARA haploinsufficiency did not alter mCG-PR dependent leukemic latency or penetrance, but did influence the distribution of leukemic cells; mCG-PR+/- x RARA+/- mice presented more commonly with low to normal white blood cell counts and with myeloid infiltration of lymph nodes. APL arising in these mice was responsive to ATRA, and had virtually no differences in expression profiling compared to tumors arising in mCG-PR+/- x RARA+/+ mice. These phenotypes were dependent on PML-RARA activity, since they were not detected in RARA+/- mice in the absence of the mCG-PR transgene. These data show that RARA haploinsufficiency (like PML haploinsufficiency and RARA-PML) can cooperate with PML-RARA to influence the pathogenesis and phenotype of APL in mice, but that PML-RARA is the driver of t(15;17) APL. RARA+/- mice were crossed with mice expressing PML-RARA from Cathepsin G locus (mCG-PR). Five leukemic mice were chosen from each of the mCG-PR+/-RARA+/- and mCG-PR+/-RARA+/+ strains and total RNA extracted from the spleen samples were analyzed using Affymetrics Mouse Exon 1.0 platform
Project description:Acute promyelocytic leukemia (APL) is associated with PML-RARA expression and late myeloid maturation arrest. The myeloid restriction of PML-RARA dependent leukemia has been recapitulated in multiple mouse models of APL, including PML-RARA expressed from the Ctsg locus (mCG-PR). However, we report here that Ctsg expression is not limited to promyelocytes (as had previously been thought); Ctsg RNA is detectable in KLS cells, and mCG-PR mice express PML-RARA within the same compartment, an event that alters multilineage hematopoiesis. However, these animals only develop myeloid leukemia (consistent with the myeloid restriction of human PML-RARA-associated leukemia). Our results suggest that APL is shaped by myeloid- and development-specific factors that define the ultimate leukemic phenotype rather than PML-RARA acting in a committed myeloid precursor.