Project description:Primary murine fetal liver cells were freshly isolated from day e14.5 livers and then sorted for successive differentiation stages by Ter119 and CD71 surface expression (ranging from double-negative CFU-Es to Ter-119 positive enucleated erythrocytes) [Zhang, et al. Blood. 2003 Dec 1; 102(12):3938-46]. RNA isolated from each freshly isolated, stage-sorted population was reverse-transcribed, labelled, and then hybridized onto 3' oligo Affymetrix arrays. Important erythroid specific genes as well as the proteins that regulate them were elucidated through this profiling based on coexpression and differential expression patterns as well as by extracting specific GO categories of genes (such as DNA-binding proteins). Abstract (submitted paper): rationale for expression profiling Gene-targeting experiments report that the homeodomain-interacting protein kinases 1 and 2, Hipk1 and Hipk2, are essential but redundant in hematopoietic developmentâbecause Hipk1/Hipk2 double-deficient animals exhibit severe defects in hematopoiesis and vasculogenesis while the single knockouts do not. These serine-threonine kinases phosphorylate, and consequently modify the functions of, several important hematopoietic transcription factors and cofactors. Here we show that Hipk2 knockdown alone plays a significant role in terminal fetal liver erythroid differentiation. Hipk1 and Hipk2 are highly induced during primary mouse fetal liver erythropoiesis. Specific knockdown of Hipk2 inhibits terminal erythroid cell proliferationâexplained in part by impaired cell cycle progression as well as increased apoptosisâand terminal enucleation as well as the accumulation of hemoglobin. Hipk2 knockdown also reduces the transcription of many genes involved in proliferation and apoptosis as well as important, erythroid-specific genes involved in hemoglobin biosynthesisâsuch as alpha-globin and mitoferrin 1âdemonstrating that Hipk2 plays an important role in some but not all aspects of normal terminal erythroid differentiation.
Project description:Using RNA-seq technology, we quantitatively determined the expression profile of microRNAs during mouse terminal erythroid differentiation. CFU-E erythroid progenitors were isolated from E14.5 fetal liver as the Ter119, B220, Mac-1, CD3 and Gr-1 negative, C-Kit positive and 20% high CD71 population. Mature Ter119+ erythroblasts were isolated from E14.5 fetal liver as C-Kit negative and Ter119 positive population. Consistent with nuclear condensation and global gene expression shut down during terminal erythroid differentiation, we found that the majority of microRNAs are downregulated in more mature Ter119+ erythroblasts compared with CFU-E erythroid progenitors. Examination of microRNA expression profiles in 2 cell types
Project description:Using RNA-seq technology, we quantitatively determined the expression profile of microRNAs during mouse terminal erythroid differentiation. CFU-E erythroid progenitors were isolated from E14.5 fetal liver as the Ter119, B220, Mac-1, CD3 and Gr-1 negative, C-Kit positive and 20% high CD71 population. Mature Ter119+ erythroblasts were isolated from E14.5 fetal liver as C-Kit negative and Ter119 positive population. Consistent with nuclear condensation and global gene expression shut down during terminal erythroid differentiation, we found that the majority of microRNAs are downregulated in more mature Ter119+ erythroblasts compared with CFU-E erythroid progenitors.
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from Mus musculus tissues (Heart, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from seven Mus musculus tissues (Heart, Brain, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:Mitochondrial tRNA taurine modifications mediated by mitochondrial tRNA translation optimization 1 (Mto1) is essential for the mitochondrial protein translation. Mto1 deficiency was shown to induce proteostress in embryonic stem cells. Recently a patient with MTO1 gene mutation presented with severe anemia was reported, which led us to hypothesize that Mto1 dysfunctions may result in defective erythropoiesis. Hematopoietic-specific Mto1 conditional knockout (cKO) mice were embryonic lethal due to niche-independent defective terminal erythroid differentiation. Mechanistically, mitochondrial oxidative phosphorylation complexes were severely impaired in the Mto1 cKO fetal liver and this was followed by cytoplasmic iron accumulation. Overloaded cytoplasmic iron promoted heme biosynthesis, which induced an unfolded protein response via the IRE1-Xbp1 signaling pathway in Mto1 cKO erythroblasts. An iron chelator rescued erythroid terminal differentiation in the Mto1 cKO fetal liver in vitro. This novel non-energy-related mitochondrial iron homeostasis revealed the indispensable role of mitochondrial tRNA modification in hematopoiesis.
Project description:Erythropoiesis is essential to mammals and is regulated at multiple steps by both extracellular and intracellular factors. Many transcriptional regulatory networks in erythroid differentiation have been well characterized. However, our understanding of post-transcriptional regulatory circuitries in this developmental process is still limited. Using genomic approaches, we identified a sequence-specific RNA-binding protein, Cpeb4, which is dramatically induced in terminal erythroid differentiation (TED) by two erythroid important transcription factors, Gata1/Tal1. Cpeb4 belongs to the cytoplasmic polyadenylation element binding (CPEB) protein family that regulates translation of target mRNAs in early embryonic development, neuronal synapse, and cancer. Using primary mouse fetal liver erythroblasts, we found that Cpeb4 is required for terminal erythropoiesis by repressing the translation of a set of mRNAs highly expressed in progenitor cells. This translational repression occurs by the interaction with a general translational initiation factor, eIF3. Interestingly, Cpeb4 also binds its own mRNA and represses its translation, thus forming a negative regulatory circuitry to limit Cpeb4 protein level. This mechanism ensures that the translation repressor, Cpeb4, does not interfere with the translation of other mRNAs in differentiating erythroblasts. Our study characterized a translational regulatorycircuitry that controls TED and revealed that Cpeb4 is required for somatic cell differentiation. We used microarray to identify mRNAs associated with Cpeb4 in mouse fetal liver erythroblasts. Cpeb4 associated mRNAs were isolated from mouse fetal liver erythroblasts using anti-Cpeb4 antibody for immunoprecipitation followed by RNA extraction. Then Affymetrix microarrays were used to identify and quantify the mRNAs associated with Cpeb4.