Project description:The formation of hematopoietic cells relies on the chromatin remodeling activities of ISWI ATPase SMARCA5 (SNF2H) and its complexes. The Smarca5 null and conditional alleles have been used to study its functions in embryonic and organ development in mice. These mouse model phenotypes vary from embryonic lethality of constitutive knockout to less severe phenotypes observed in tissue-specific Smarca5 deletions, e.g., in the hematopoietic system. Here we show that, in a gene dosage-dependent manner, the hypomorphic allele of SMARCA5 (S5tg) can rescue not only the developmental arrest in hematopoiesis in the hCD2iCre model but also the lethal phenotypes associated with constitutive Smarca5 deletion or Vav1iCre-driven conditional knockout in hematopoietic progenitor cells. Interestingly, the latter model also provided evidence for the role of SMARCA5 expression level in hematopoietic stem cells, as the Vav1iCre S5tg animals accumulate stem and progenitor cells. Furthermore, their hematopoietic stem cells exhibited impaired lymphoid lineage entry and differentiation. This observation contrasts with the myeloid lineage which is developing without significant disturbances. Our findings indicate that animals with low expression of SMARCA5 exhibit normal embryonic development with altered lymphoid entry within the hematopoietic stem cell compartment.
Project description:A transcriptome study in mouse hematopoietic stem cells was performed using a sensitive SAGE method, in an attempt to detect medium and low abundant transcripts expressed in these cells. Among a total of 31,380 unique transcript, 17,326 (55%) known genes were detected, 14,054 (45%) low-copy transcripts that have no matches to currently known genes. 3,899 (23%) were alternatively spliced transcripts of the known genes and 3,754 (22%) represent anti-sense transcripts from known genes.
Project description:Meis1 encodes a TALE family homeodomain protein that was first identified as a common retroviral integration site in mouse BHX2 myeloid leukemia. It functions as a DNA binding co-factor of Hox proteins through interacting with Pbx, a member of another TALE family protein. Moreover, Meis1 homozygous knockout mice are embryonic lethal, showing significant defects in vasculogenesis, eye development and hematopoiesis. Severe defects were also observed in adult hematopoiesis by conditional inactivation of Meis1 in vivo. Meis1 is critical to maintain the balance between enter and exit from cell cycles of hematopoietic stem cells (HSCs), indicating that Meis1 regulates self-renewal and quiescence of HSCs. Total RNA was isolated from KSL cells obtained from poly(I:C)-treated Mx1-Cre Meis1fl/fl and sham-treated Meis1fl/fl mice.
Project description:Meis1 encodes a TALE family homeodomain protein that was first identified as a common retroviral integration site in mouse BHX2 myeloid leukemia. It functions as a DNA binding co-factor of Hox proteins through interacting with Pbx, a member of another TALE family protein. Moreover, Meis1 homozygous knockout mice are embryonic lethal, showing significant defects in vasculogenesis, eye development and hematopoiesis. Severe defects were also observed in adult hematopoiesis by conditional inactivation of Meis1 in vivo. Meis1 is critical to maintain the balance between enter and exit from cell cycles of hematopoietic stem cells (HSCs), indicating that Meis1 regulates self-renewal and quiescence of HSCs.
Project description:A transcriptome study in mouse hematopoietic stem cells was performed using a sensitive SAGE method, in an attempt to detect medium and low abundant transcripts expressed in these cells. Among a total of 31,380 unique transcript, 17,326 (55%) known genes were detected, 14,054 (45%) low-copy transcripts that have no matches to currently known genes. 3,899 (23%) were alternatively spliced transcripts of the known genes and 3,754 (22%) represent anti-sense transcripts from known genes. Mouse hematopoietic stem cells were purified from bone marrow cells using negative and positive selection with a Magnetic-Activated Cell Sorter (MACS). total RNA and mRNA were purified from the purified cells using Trizol reagent and magnetic oligo dT beads. Double strand cDNAs were synthesized using a cDNA synthesis kit and anchored oligo dT primers. After NlaIII digestion, 3’ cDNAs were isolated and amplified through 16-cycle PCR. SAGE tags were released from the 3’ cDNA after linker ligation. Ditags were formed, concatemerized and cloned into a pZERO vector. Sequencing reactions were performed with the ET sequencing terminator kit. Sequences were collected using a Megabase 1000 sequencer. SAGE tag sequences were extracted using SAGE 2000 software.
Project description:The fate options of hematopoietic stem cells (HSCs) include self-renewal, differentiation, migration and apoptosis, but the interaction between intracellular Ca2+ and cytoplasmic chaperon protein in regulating fate options of long term-HSCs (LT-HSC) is unknown. We created a S100A6 conditional knockout mouse model in the hematopoietic system and our studies showed that in S100A6KO, the number of LT-HSCs was significantly reduced and HSCs engrafted poorly. After 5FU challenge, the frequency of S100A6KO HSCs remained significantly low. Our data showed that S100A6 failed to self-renew through Akt pathway in an intracellular calcium (Cai2+)-dependent manner. Expression profiling of S100A6KO obtained from gene signatures revealed that cytosolic calcium level and proteins translocation to mitochondria were decreased. Mitochondrial oxidative phosphorylation was impaired in S100A6KO. Proteomic data indicated Hsp90 protein and chaperonin family were reduced. Our findings demonstrated that S100A6 regulates fate options of HSCs self-renewal through integrating Akt signaling, specifically governing mitochondria metabolic function and protein quality.