Molecular analysis of the mouse S100A9 gene and evidence that the myeloid specific transcription factor C/EBPepsilon is not required for the regulation of the S100A9/A8 gene expression in neutrophils

AbstractMutations in the transcription factor C/EBPα are found in ~10% of all acute myeloid leukaemia (AML) cases but the contribution of these mutations to leukemogenesis is incompletely understood. We here use a mouse model of granulocyte progenitors expressing conditionally active HoxB8 to assess the cell biological and molecular activity of C/EBPα-mutations associated with human AML. Both N-terminal truncation and C-terminal AML-associated mutations of C/EBPα substantially altered differentiation of progenitors into mature neutrophils in cell culture. Closer analysis of the C/EBPα-K313-duplication showed expansion and prolonged survival of mutant C/EBPα-expressing granulocytes following adoptive transfer into mice. C/EBPα-protein containing the K313-mutation further showed strongly enhanced transcriptional activity compared with the wild-type protein at certain promoters. Analysis of differentially regulated genes in cells overexpressing C/EBPα-K313 indicates a strong correlation with genes regulated by C/EBPα. Analysis of transcription factor enrichment in the differentially regulated genes indicated a strong reliance of SPI1/PU.1, suggesting that despite reduced DNA binding, C/EBPα-K313 is active in regulating target gene expression and acts largely through a network of other transcription factors. Strikingly, the K313 mutation caused strongly elevated expression of C/EBPα-protein, which could also be seen in primary K313 mutated AML blasts, explaining the enhanced C/EBPα activity in K313-expressing cells.

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Role of a pituitary-specific transcription factor (pit-1/GHF-1) or a closely related protein in cAMP regulation of human thyrotropin-beta subunit gene expression.

Journal of Clinical Investigation ◽

10.1172/jci115600 ◽

1992 ◽

Vol 89 (2) ◽

pp. 409-419 ◽

Cited By ~ 43

Author(s):

H J Steinfelder ◽

S Radovick ◽

M A Mroczynski ◽

P Hauser ◽

J H McClaskey ◽

...

Keyword(s):

Gene Expression ◽

Transcription Factor ◽

Beta Subunit ◽

Related Protein ◽

Subunit Gene ◽

Specific Transcription Factor ◽

Beta Subunit Gene

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Epigenetic Control of C/EBPa by Noncoding RNAs.

Blood ◽

10.1182/blood.v114.22.3644.3644 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3644-3644

Author(s):

Annalisa Di Ruscio ◽

Alexander K Ebralidze ◽

Francesco D'Alò ◽

Maria Teresa Voso ◽

Giuseppe Leone ◽

...

Keyword(s):

Gene Expression ◽

Transcription Factor ◽

Messenger Rna ◽

Noncoding Rna ◽

Gene Locus ◽

Conflicts Of Interest ◽

Lentiviral Vector ◽

Rt Pcr ◽

Hematopoietic Stem ◽

Factor C

Abstract Abstract 3644 Poster Board III-580 Little is currently known about the role of noncoding RNA transcripts (ncRNA) in gene regulation; although most, and perhaps all, gene loci express such transcripts. Our previous results with the PU.1 gene locus showed a shared transcription factor complex and chromatin configuration requirements for biogenesis of both messenger and ncRNAs. These ncRNAs were localized within the nuclear and cytoplasmic compartments. Disrupting ncRNAs in the cytoplasmic cellular fraction results in increased PU.1 mRNA and protein. Recently, we have focused on the C/EBPa gene locus and observed extensive noncoding transcription. The transcription factor C/EBPa plays a pivotal role in hematopoietic stem cell (HSC) commitment and differentiation. Expression of the C/EBPa gene is tightly regulated during normal hematopoietic development, and dysregulation of C/EBPa expression can lead to lung cancer and leukemia. However, little is known about how the C/EBPa gene is regulated in vivo. In this study, we characterize ncRNAs derived from the C/EBPa locus and demonstrate their functional role in regulation of C/EBPa gene expression. First, northern blot analysis and RT PCR determined a predominantly nuclear localization of the C/EBPa ncRNAs. Second, strand-specific quantitative RT PCR demonstrated a concordant expression of coding and noncoding C/EBPa transcripts. Next, we investigated the results of ablation of ncRNAs using a lentiviral vector containing ncRNA-targeting shRNAs on the expression of the C/EBPa gene. We have observed that reduced levels of ncRNAs leads to a significant downregulation of the expression of coding messenger RNA. These data strongly suggest that C/EBPa ncRNAs play an important role in maintaining optimal expression of the C/EBPa gene at different stages of hematopoiesis and makes targeting noncoding transcripts a novel and attractive tool in correcting aberrant gene expression levels. Disclosures: No relevant conflicts of interest to declare.

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