Publications by authors named "Almira Chervova"

3 Publications

  • Page 1 of 1

The combined action of Esrrb and Nr5a2 is essential for murine naïve pluripotency.

Development 2021 Sep 10;148(17). Epub 2021 Sep 10.

Epigenomics, Proliferation, and the Identity of Cells, Department of Developmental and Stem Cell Biology, Institut Pasteur, CNRS UMR3738, 75015 Paris, France.

The maintenance of pluripotency in mouse embryonic stem cells (ESCs) is governed by the action of an interconnected network of transcription factors. Among them, only Oct4 and Sox2 have been shown to be strictly required for the self-renewal of ESCs and pluripotency, particularly in culture conditions in which differentiation cues are chemically inhibited. Here, we report that the conjunct activity of two orphan nuclear receptors, Esrrb and Nr5a2, parallels the importance of that of Oct4 and Sox2 in naïve mouse ESCs. By occupying a large common set of regulatory elements, these two factors control the binding of Oct4, Sox2 and Nanog to DNA. Consequently, in their absence the pluripotency network collapses and the transcriptome is substantially deregulated, leading to the differentiation of ESCs. Altogether, this work identifies orphan nuclear receptors, previously thought to be performing supportive functions, as a set of core regulators of naïve pluripotency.
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http://dx.doi.org/10.1242/dev.199604DOI Listing
September 2021

Analysis of gene expression and mutation data points on contribution of transcription to the mutagenesis by APOBEC enzymes.

NAR Cancer 2021 09 2;3(3):zcab025. Epub 2021 Jul 2.

Research and Training Center of Bioinformatics, Institute for Information Transmission Problems (the Kharkevich Institute, RAS), Moscow, 127051, Russia.

Since the discovery of the role of the APOBEC enzymes in human cancers, the mechanisms of this type of mutagenesis remain little understood. Theoretically, targeting of single-stranded DNA by the APOBEC enzymes could occur during cellular processes leading to the unwinding of DNA double-stranded structure. Some evidence points to the importance of replication in the APOBEC mutagenesis, while the role of transcription is still underexplored. Here, we analyzed gene expression and whole genome sequencing data from five types of human cancers with substantial APOBEC activity to estimate the involvement of transcription in the APOBEC mutagenesis and compare its impact with that of replication. Using the TCN motif as the mutation signature of the APOBEC enzymes, we observed a correlation of active APOBEC mutagenesis with gene expression, confirmed the increase of APOBEC-induced mutations in early-replicating regions and estimated the relative impact of transcription and replication on the APOBEC mutagenesis. We also found that the known effect of higher density of APOBEC-induced mutations on the lagging strand was highest in middle-replicating regions and observed higher APOBEC mutation density on the sense strand, the latter bias positively correlated with the gene expression level.
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http://dx.doi.org/10.1093/narcan/zcab025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8253550PMC
September 2021

Reduced vs. standard dose native E. coli-asparaginase therapy in childhood acute lymphoblastic leukemia: long-term results of the randomized trial Moscow-Berlin 2002.

J Cancer Res Clin Oncol 2019 Apr 6;145(4):1001-1012. Epub 2019 Mar 6.

Department of Pediatric Oncology/Hematology, Regional Oncological Hospital, Orenburg, Russia.

Purpose: Favorable outcomes were achieved for children with acute lymphoblastic leukemia (ALL) with the first Russian multicenter trial Moscow-Berlin (ALL-MB) 91. One major component of this regimen included a total of 18 doses of weekly intramuscular (IM) native Escherichia coli-derived asparaginase (E. coli-ASP) at 10000 U/m during three consolidation courses. ASP was initially available from Latvia, but had to be purchased from abroad at substantial costs after the collapse of Soviet Union. Therefore, the subsequent trial ALL-MB 2002 aimed at limiting costs to a reasonable extent and also at reducing toxicity by lowering the dose for standard risk (SR-) patients to 5000 U/m without jeopardizing efficacy.

Methods: Between April 2002 and November 2006, 774 SR patients were registered in 34 centers across Russia and Belarus, 688 of whom were randomized. In arm ASP-5000 (n = 334), patients received 5000 U/m and in arm ASP-10000 (n = 354) 10 000 U/m IM.

Results: Probabilities of disease-free survival, overall survival and cumulative incidence of relapse at 10 years were comparable: 79 ± 2%, 86 ± 2% and 17.4 ± 2.1% (ASP-5000) vs. 75 ± 2% and 82 ± 2%, and 17.9 ± 2.0% (ASP-10000), while death in complete remission was significantly lower in arm ASP-5000 (2.7% vs. 6.5%; p = 0.029).

Conclusion: Our findings suggest that weekly 5000 U/mE. coli-ASP IM during consolidation therapy are equally effective, more cost-efficient and less toxic than 10000 U/m for SR patients with childhood ALL.
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http://dx.doi.org/10.1007/s00432-019-02854-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6435612PMC
April 2019
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