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Dive into the research topics where Galina V. Ermakova is active.

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Featured researches published by Galina V. Ermakova.


Nature Methods | 2007

Bright far-red fluorescent protein for whole-body imaging.

Dmitry Shcherbo; Ekaterina M. Merzlyak; Tatiana V. Chepurnykh; Arkady F. Fradkov; Galina V. Ermakova; Elena A. Solovieva; Konstantin A. Lukyanov; Ekaterina A. Bogdanova; Andrey G. Zaraisky; Sergey Lukyanov; Dmitriy M. Chudakov

For deep imaging of animal tissues, the optical window favorable for light penetration is in near-infrared wavelengths, which requires proteins with emission spectra in the far-red wavelengths. Here we report a far-red fluorescent protein, named Katushka, which is seven- to tenfold brighter compared to the spectrally close HcRed or mPlum, and is characterized by fast maturation as well as a high pH-stability and photostability. These unique characteristics make Katushka the protein of choice for visualization in living tissues. We demonstrate superiority of Katushka for whole-body imaging by direct comparison with other red and far-red fluorescent proteins. We also describe a monomeric version of Katushka, named mKate, which is characterized by high brightness and photostability, and should be an excellent fluorescent label for protein tagging in the far-red part of the spectrum.


Biochemical Journal | 2009

Far-red fluorescent tags for protein imaging in living tissues

Dmitry Shcherbo; Christopher S. Murphy; Galina V. Ermakova; Elena A. Solovieva; Tatiana V. Chepurnykh; Aleksandr S. Shcheglov; Vladislav V. Verkhusha; Vladimir Z. Pletnev; Kristin L. Hazelwood; Patrick M. Roche; Sergey Lukyanov; Andrey G. Zaraisky; Michael W. Davidson; Dmitriy M. Chudakov

A vast colour palette of monomeric fluorescent proteins has been developed to investigate protein localization, motility and interactions. However, low brightness has remained a problem in far-red variants, which hampers multicolour labelling and whole-body imaging techniques. In the present paper, we report mKate2, a monomeric far-red fluorescent protein that is almost 3-fold brighter than the previously reported mKate and is 10-fold brighter than mPlum. The high-brightness, far-red emission spectrum, excellent pH resistance and photostability, coupled with low toxicity demonstrated in transgenic Xenopus laevis embryos, make mKate2 a superior fluorescent tag for imaging in living tissues. We also report tdKatushka2, a tandem far-red tag that performs well in fusions, provides 4-fold brighter near-IR fluorescence compared with mRaspberry or mCherry, and is 20-fold brighter than mPlum. Together, monomeric mKate2 and pseudo-monomeric tdKatushka2 represent the next generation of extra-bright far-red fluorescent probes offering novel possibilities for fluorescent imaging of proteins in living cells and animals.


Gene | 1997

Anf: A novel class of vertebrate homeobox genes expressed at the anterior end of the main embryonic axis

Olga V. Kazanskaya; Elena A. Severtzova; K. Anukampa Barth; Galina V. Ermakova; Sergey Lukyanov; Alex O. Benyumov; Maria Pannese; Edoardo Boncinelli; Stephen W. Wilson; Andrey G. Zaraisky

Five novel genes homologous to the homeobox-containing genes Xanf-1 and Xanf-2 of Xenopus and Hesx-1/Rpx of mouse have been identified as a result of a PCR survey of cDNA in sturgeon, zebrafish, newt, chicken and human. Comparative analysis of the homeodomain primary structure of these genes revealed that they belong to a novel class of homeobox genes, which we name Anf. All genes of this class investigated so far have similar patterns of expression during early embryogenesis, characterized by maximal transcript levels being present at the anterior extremity of the main embryonic body axis. The data obtained also suggest that, despite considerable high structural divergence between their homeodomains, all known Anf genes may be orthologues, and thus represent one of the most quickly evolving classes of vertebrate homeobox genes.


Development | 2004

Patterning the forebrain: FoxA4a/Pintallavis and Xvent2 determine the posterior limit of Xanf1 expression in the neural plate

N. Y. Martynova; Fedor M. Eroshkin; Galina V. Ermakova; Andrey V. Bayramov; Jessica Gray; Robert M. Grainger; Andrey G. Zaraisky

During early development of the nervous system in vertebrates, expression of the homeobox gene Anf/Hesx1/Rpx is restricted to the anterior neural plate subdomain corresponding to the presumptive forebrain. This expression is essential for normal forebrain development and ectopic expression of Xenopus Anf, Xanf1 (also known as Xanf-1), results in severe forebrain abnormalities. By use of transgenic embryos and a novel bi-colour reporter technique, we have identified a cis-regulatory element responsible for transcriptional repression of Xanf1 that defines its posterior expression limit within the neural plate. Using this element as the target in a yeast one-hybrid system, we identified two transcription factors, FoxA4a/Pintallavis and Xvent2 (also known as Xvent-2), which are normally expressed posterior to Xanf1. Overexpression of normal and dominant-negative versions of these factors, as well as inhibition of their mRNA translation by antisense morpholinos, show that they actually function as transcriptional repressors of Xanf1 just behind its posterior expression limit. The extremely high similarity of the identified Anf cis-regulatory sequences in Xenopus, chick and human, indicates that the mechanism restricting posterior expression of Anf in Xenopus is shared among vertebrates. Our findings support Nieuwkoops activation-transformation model for neural patterning, according to which the entire neurectoderm is initially specified towards an anterior fate, which is later suppressed posteriorly as part of the trunk formation process.


Biochemical Journal | 2011

Light-induced blockage of cell division with a chromatin-targeted phototoxic fluorescent protein

Ekaterina O. Serebrovskaya; Tatiana V. Gorodnicheva; Galina V. Ermakova; Elena A. Solovieva; George V. Sharonov; Elena V. Zagaynova; Dmitriy M. Chudakov; Sergey Lukyanov; Andrey G. Zaraisky; Konstantin A. Lukyanov

Proteins of the GFP (green fluorescent protein) family are widely used as passive reporters for live cell imaging. In the present study we used H2B (histone H2B)-tKR (tandem KillerRed) as an active tool to affect cell division with light. We demonstrated that H2B-tKR-expressing cells behave normally in the dark, but transiently cease proliferation following green-light illumination. Complete light-induced blockage of cell division for approx. 24 h was observed in cultured mammalian cells that were either transiently or stably transfected with H2B-tKR. Illuminated cells then returned to normal division rate. XRCC1 (X-ray cross complementing factor 1) showed immediate redistribution in the illuminated nuclei of H2B-tKR-expressing cells, indicating massive light-induced damage of genomic DNA. Notably, nondisjunction of chromosomes was observed for cells that were illuminated during metaphase. In transgenic Xenopus embryos expressing H2B-tKR under the control of tissue-specific promoters, we observed clear retardation of the development of these tissues in green-light-illuminated tadpoles. We believe that H2B-tKR represents a novel optogenetic tool, which can be used to study mitosis and meiosis progression per se, as well as to investigate the roles of specific cell populations in development, regeneration and carcinogenesis in vivo.


Biochimica et Biophysica Acta | 2015

Fluorescent ratiometric pH indicator SypHer2: Applications in neuroscience and regenerative biology.

Mikhail E. Matlashov; Yulia A. Bogdanova; Galina V. Ermakova; Natalia M. Mishina; Yulia G. Ermakova; Evgeny S. Nikitin; P. M. Balaban; Shigeo Okabe; Sergey Lukyanov; Grigori Enikolopov; Andrey G. Zaraisky; Vsevolod V. Belousov

BACKGROUND SypHer is a genetically encoded fluorescent pH-indicator with a ratiometric readout, suitable for measuring fast intracellular pH shifts. However, the relatively low brightness of the indicator limits its use. METHODS Here we designed a new version of pH-sensor called SypHer-2, which has up to three times brighter fluorescence in cultured mammalian cells compared to the SypHer. RESULTS Using the new indicator we registered activity-associated pH oscillations in neuronal cell culture. We observed prominent transient neuronal cytoplasm acidification that occurs in parallel with calcium entry. Furthermore, we monitored pH in presynaptic and postsynaptic termini by targeting SypHer-2 directly to these compartments and revealed marked differences in pH dynamics between synaptic boutons and dendritic spines. Finally, we were able to reveal for the first time the intracellular pH drop that occurs within an extended region of the amputated tail of the Xenopus laevis tadpole before it begins to regenerate. CONCLUSIONS SypHer2 is suitable for quantitative monitoring of pH in biological systems of different scales, from small cellular subcompartments to animal tissues in vivo. GENERAL SIGNIFICANCE The new pH-sensor will help to investigate pH-dependent processes in both in vitro and in vivo studies.


Gene Expression Patterns | 2003

Expression zones of three novel genes abut the developing anterior neural plate of Xenopus embryo.

V.V Novoselov; E.M Alexandrova; Galina V. Ermakova; Andrey G. Zaraisky

We identified three novel genes that were expressed within the anterior non-neural ectoderm of Xenopus early neurula embryos. The expression of these genes was observed in the different areas complementary to the expression zone of a homeodomain gene Xanf-1 in the anterior neural plate. One of these genes, a Ras-like GTP-ase Ras-dva, marked the anterior placodal ectoderm area; a second, an Agr family homologous gene, XAgr2, was expressed in the anterior-most ectoderm in the cement gland primordium, and a third, novel gene Nlo was expressed in the lateral neural folds. The genes were transiently expressed in the developing cement and hatching gland primordia, and repressed in the mature cement and hatching glands. XAgr2 and Nlo were also expressed in the otic vesicles, and Ras-dva was expressed in the dorso-lateral column of the neural tube.


Scientific Reports | 2013

Agr genes, missing in amniotes, are involved in the body appendages regeneration in frog tadpoles

Anastasiya S. Ivanova; Maria B. Tereshina; Galina V. Ermakova; Vsevolod V. Belousov; Andrey G. Zaraisky

Previous studies have shown that Agr genes, which encode thioredoxin domain-containing secreted proteins, play a critical role in limb regeneration in salamanders. To determine the evolutionary conservation of Agr function, it is important to examine whether Agrs play a similar role in species with a different type of regeneration. Here, we refined the phylogeny of Agrs, revealing three subfamilies: Ag1, Agr2 and Agr3. Importantly, we established that Ag1 was lost in higher vertebrates, which correlates with their decreased regeneration ability. In Xenopus laevis tadpoles (anamniotes), which have all three Agr subfamilies and a high regenerating capacity, Agrs were activated in the stumps of tails and hindlimb buds that were amputated at stage 52. However, Agrs were not up-regulated when the hindlimb buds were amputated at stage 57, the stage at which their regeneration capacity is lost. Our findings indicate the general importance of Agrs for body appendages regeneration in amphibians.


Developmental Dynamics | 2008

The LIM-domain protein Zyxin binds the homeodomain factor Xanf1/Hesx1 and modulates its activity in the anterior neural plate of Xenopus laevis embryo

N. Y. Martynova; Fedor M. Eroshkin; L. V. Ermolina; Galina V. Ermakova; Anastasia L. Korotaeva; K. M. Smurova; Fatima K. Gyoeva; Andrey G. Zaraisky

The question of how subdivision of embryo into cell territories acquiring different fates is coordinated with morphogenetic movements shaping the embryonic body still remains poorly resolved. In the present report, we demonstrate that a key regulator of anterior neural plate patterning, the homeodomain transcriptional repressor Xanf1/Hesx1, can bind to the LIM‐domain protein Zyxin, which is known to regulate cell morphogenetic movements via influence on actin cytoskeleton dynamics. Using a set of deletion mutants, we found that the Engrailed‐type repressor domain of Xanf1 and LIM2‐domain of Zyxin are primarily responsible for interaction of these proteins. We also demonstrate that Zyxin overexpression in Xenopus embryos elicits effects similar to those observed in embryos with downregulated Xanf1. In contrast, when the repressor‐fused variant of Zyxin is expressed, the forebrain enlargements typical for embryos overexpressing Xanf1 develop. These results are consistent with a possible role of Zyxin as a negative modulator of Xanf1 transcriptional repressing activity. Developmental Dynamics 237:736–749, 2008.


Scientific Reports | 2016

Noggin4 is a long-range inhibitor of Wnt8 signalling that regulates head development in Xenopus laevis

Fedor M. Eroshkin; Alexey M. Nesterenko; A. V. Borodulin; N. Y. Martynova; Galina V. Ermakova; Fatima K. Gyoeva; E. E. Orlov; A. A. Belogurov; Konstantin A. Lukyanov; Andrey V. Bayramov; Andrey G. Zaraisky

Noggin4 is a Noggin family secreted protein whose molecular and physiological functions remain unknown. In this study, we demonstrate that in contrast to other Noggins, Xenopus laevis Noggin4 cannot antagonise BMP signalling; instead, it specifically binds to Wnt8 and inhibits the Wnt/β -catenin pathway. Live imaging demonstrated that Noggin4 diffusivity in embryonic tissues significantly exceeded that of other Noggins. Using the Fluorescence Recovery After Photobleaching (FRAP) assay and mathematical modelling, we directly estimated the affinity of Noggin4 for Wnt8 in living embryos and determined that Noggin4 fine-tune the Wnt8 posterior-to-anterior gradient. Our results suggest a role for Noggin4 as a unique, freely diffusing, long-range inhibitor of canonical Wnt signalling, thus explaining its ability to promote head development.

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Andrey G. Zaraisky

Russian Academy of Sciences

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N. Y. Martynova

Russian Academy of Sciences

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Fedor M. Eroshkin

Russian Academy of Sciences

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Andrey V. Bayramov

Russian Academy of Sciences

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Elena A. Solovieva

Russian Academy of Sciences

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Sergey Lukyanov

Russian National Research Medical University

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Konstantin A. Lukyanov

Nizhny Novgorod State Medical Academy

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Maria B. Tereshina

Russian Academy of Sciences

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Dmitriy M. Chudakov

Russian National Research Medical University

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