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: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.
Project description:Coordination of cellular processes through the establishment of tissue-specific gene expression programmes is essential for lineage maturation. The basic helix-loop-helix haemopoietic transcriptional regulator SCL/Tal1 is required for terminal differentiation of red blood cells. To gain insight into SCL function and mechanisms of action in erythropoiesis, we performed ChIP-sequencing and gene expression analyses from primary fetal liver erythroid cells. We show that SCL coordinates expression of genes in most known red cell-specific processes. The majority of SCLâs genomic targets require direct DNA-binding activity. However, one fifth of SCLâs target sequences, mainly amongst those showing high affinity for SCL, can recruit the factor independently of its DNA binding activity. An unbiased DNA motif search of sequences bound by SCL identified CAGNTG as SCL-preferred E-box motif in erythroid cells. Novel motifs were also characterised that may help distinguish activated from repressed genes and suggest a new mechanism by which SCL may be recruited to DNA. Finally, analysis of recruitment of GATA1, a protein partner of SCL, to sequences occupied by SCL suggests that SCLâs binding is necessary prior or simultaneous to that of GATA1. This work provides the framework to study regulatory networks leading to erythroid terminal maturation and to model mechanisms of action of tissue-specific transcription factors. Total RNA extracted from wild-type (WT) day E12.5 fetal liver Ter119- erythroid progenitor cells was compared to total RNA extracted from E12.5 fetal liver Ter119- cells expressing a DNA-binding mutant form of SCL (SclRER/RER).