Project description:The AMV v-Myb oncoprotein causes oncogenic transformation of myelomonocytic cells in vivo and in vitro. Its transforming capacity is strictly dependent upon the N-terminal DNA binding domain, the central transactivation region, and on the C-terminal domain containing a putative leucine zipper motif. While deletions in the central part of the leucine zipper region or point mutations of critical leucine residues abolish the leukemogenicity of the protein, a small deletion within the N-terminal part (deltaP mutant) preserves almost full in vitro transforming ability and only weakens the leukemogenic potential in vivo. We analyzed the gene expression profiles of ex vivo cultures transformed with either wild type or deltaP mutant of v-Myb. A few tens of genes were found to be significantly and reproducibly differentially expressed between the two cultures. Among them, the transcript of the CDKN2A gene, which is critically involved in the cell cycle progression regulation, showed higher expression in the deltaP mutant transformed cells. In mammals and also some avian species, there are two different mRNAs - ARF and INK4A – transcribed from the CDKN2A locus. It is known that in chickens the locus had been rearranged in evolution and only one mRNA is transcribed. We found that this mRNA encodes both ARF and INK4A and that the INK4A protein translation starts with a GUG codon downstream of the ARF AUG initiation codon and proceeds in a different reading frame. INK4A protein thus exists in chicken cells as well and its negative regulation by v-Myb is a part of the leukemic transformation mechanism. Comparison of expression profiles of chicken monoblasts transformed either by wild type v-myb or its mutated version designated deltaP. Three biological replicates were analyzed for each group.
Project description:The AMV v-Myb oncoprotein causes oncogenic transformation of myelomonocytic cells in vivo and in vitro. Its transforming capacity is strictly dependent upon the N-terminal DNA binding domain, the central transactivation region, and on the C-terminal domain containing a putative leucine zipper motif. While deletions in the central part of the leucine zipper region or point mutations of critical leucine residues abolish the leukemogenicity of the protein, a small deletion within the N-terminal part (deltaP mutant) preserves almost full in vitro transforming ability and only weakens the leukemogenic potential in vivo. We analyzed the gene expression profiles of ex vivo cultures transformed with either wild type or deltaP mutant of v-Myb. A few tens of genes were found to be significantly and reproducibly differentially expressed between the two cultures. Among them, the transcript of the CDKN2A gene, which is critically involved in the cell cycle progression regulation, showed higher expression in the deltaP mutant transformed cells. In mammals and also some avian species, there are two different mRNAs - ARF and INK4A – transcribed from the CDKN2A locus. It is known that in chickens the locus had been rearranged in evolution and only one mRNA is transcribed. We found that this mRNA encodes both ARF and INK4A and that the INK4A protein translation starts with a GUG codon downstream of the ARF AUG initiation codon and proceeds in a different reading frame. INK4A protein thus exists in chicken cells as well and its negative regulation by v-Myb is a part of the leukemic transformation mechanism.
Project description:Identification of de novo copy number abnormalities arising in relapsed paediatric ALL in matched presentation and relapse samples. We identified deletions of BACH2, (BTB and CNC homology 1, basic leucine zipper transcription factor 2) at relapse. To study the role of Bach2 in pre-B ALL in a genetic experiment, we transformed pre-B cells from Bach2–/– mice with BCR-ABL1. Our findings identify Bach2 as a novel tumor suppressor upstream of p53 in pre-B ALL.
Project description:Most transcription factors possess at least one long intrinsically disordered transactivation domain that binds to a variety of co-activators and co-repressors and plays a key role in modulating the transcriptional activity. Despite the crucial importance of these mechanisms, the structural and functional basis of transactivation domain in yet poorly understood. Here, we focused on ATF4/CREB-2, an essential transcription factor for cellular stress adaptation. We found that the N-terminal region of the transactivation domain is involved in transient long-range interactions with the basic-leucine zipper domain. In vitro phosphorylation assays with the protein kinase CK2 show that the presence of the basic-leucine zipper domain is required for optimal phosphorylation of the transactivation domain. This study uncovers the intricate coupling existing between the transactivation and basic-leucine zipper domains of ATF4 and highlights its potential functional relevance.
Project description:The neural crest (NC) is a transient dynamic structure of ectodermal origin, found in early vertebrate embryos. The multipotential NC cells migrate along well defined routes, differentiate to various cells types including melanocytes and participate in the formation of various permanent tissues. Abnormal development of NC cells causes several human diseases M-bM-^@M-^S neurocristopathies. As there is only limited information about the molecular mechanisms controlling early events in melanocyte specification and development, we exploited the AMV v-Myb transcriptional regulator, which directs differentiation of in vitro chicken NC cells to the melanocyte lineage. This activity is strictly dependent on v-Myb specifically binding to the Myb recognition DNA element (MRE). The two tamoxifen-inducible v-myb alleles were constructed, one which recognizes the MRE and one which does not. These were activated in ex-ovo NC cells, and the expression profiles of resulting cells were analyzed using Affymetrix microarrays and RT-PCR. These approaches revealed up-regulation of the BMP antagonist gremlin 2 mRNA, and down-regulation of mRNAs encoding several epithelial genes including KRT19 as very early events following the activation of melanocyte differentiation by v-Myb. Comparison of gene expression profiles of chicken neural crest cells constitutively expressing 4-OH-tamoxifen inducible v-myb with mutated leucine zipper region or a version with an additional point mutation (N118D) in the DNA-binding domain. Three biological replicates were analyzed for each group.
Project description:Deep mutational scanning of the interaction of JUN's leucine zipper domain and other human bZIPs in different experimental conditions
Project description:Identification of de novo copy number abnormalities arising in relapsed paediatric ALL in matched presentation and relapse samples. We identified deletions of BACH2, (BTB and CNC homology 1, basic leucine zipper transcription factor 2) at relapse. To study the role of Bach2 in pre-B ALL in a genetic experiment, we transformed pre-B cells from Bach2–/– mice with BCR-ABL1. Our findings identify Bach2 as a novel tumor suppressor upstream of p53 in pre-B ALL. 64 arrays (32 250K Nsp and 32 250K Sty) are included in this study. DNA was extracted from the presentation and relapse samples from 11 paediatric patients and DNA was extarcted from the remission samples from 10 patient and hybridised to the Affymetrix Human Mapping 500K Array Set.
Project description:To investigate the downstream targets of eIF5 mimic protein 1 (5MP1), also known as Basic Leucine Zipper and W2 domains 2 (BZW2; Ensembl:ENSG00000136261), we performed a transcriptomic analysis using high throoughput RNA sequencing (RNA-seq).
Project description:Basic leucine zipper and W2 domains 2 (BZW2), also known as translation initiation regulator eIF5-mimic protein 1 (5MP1), is a member of the basic‐region leucine zipper (bZIP) superfamily of transcription factors. BZW2 has partial homology with eIF5 and can function as a competitive inhibitor of eIF5. In human Colorectal cancers, high mRNA and protein expression levels of BZW2 were associated with tumor progression. BZW2-knockdown reduced malignant phenotypes, including cell proliferation, invasion, and spheroid and colony formation. BZW2-knockdown also reduced tumor growth and metastasis In summary, our study characterizes the expression BZW2 in colorectal cancer and explore its regulation mechanism. Future studies are needed to decipher the biological significance of these findings.