Sergei A. Lukyanov

Scientific interests

Sergei Lukyanov’s basic scientific interests lie in the area of analysis of structure and functioning of eukaryotic genomes.

Awards & honors

Sergei Lukyanov has been awarded the Ovchinnikov prize of the Russian Academy of Sciences in the field of physico-chemical biology and biotechnology for his work “Fluorescent proteins: finding, investigation and use in biotechnology” (2006), the international academic publisher “Nauka” prizes for best publication (1996 and 1999), prizes for best publication in Russian Journal of Bioorganic Chemistry (1996, 1997 and 1999), "Outstanding scientists“scholarship and a “State Scientific Scholarship” grant.

Main scientific results

The methods based on the Selective Suppression of Polymerase Chain Reaction — effect discovered by Lukyanov, are widely used in molecular biology labs in Russia and over the world. The technologies using Duplex-Specific Nuclease — enzyme isolated and characterized in collaboration with the laboratory of Marine Biochemistry of the Pacific Institute of Bioorganic Chemistry (headed by Professor V.A. Rasskazov), — have also found broad application. Lukyanov’s research on fluorescent proteins has revolutionized in vivo labeling technologies and brought him wide international recognition.

Selected publications

  1. Shagina I., Bogdanova E., Mamedov I., Lebedev Y., Lukyanov S., Shagin D. (2010). Normalization of genomic DNA using duplex-specific nuclease. BioTechniques 48 (6), 351–355 [+]

    An application of duplex-specific nuclease (DSN) normalization technology to whole-genome shotgun sequencing of genomes with a large proportion of repetitive DNA is described. The method uses a thermostable DSN from the Kamchatka crab that specifically hydrolyzes dsDNA. In model experiments on human genomic DNA, we demonstrated that DSN normalization of double-stranded DNA formed during C0t analysis is effective against abundant repetitive sequences with high sequence identity, while retaining highly divergent repeats and coding regions at baseline levels. Thus, DSN normalization applied to C0t analysis can be used to eliminate evolutionarily young repetitive elements from genomic DNA before sequencing, and should prove invaluable in studies of large eukaryotic genomes, such as those of higher plants.

  2. Bogdanov A.M., Bogdanova E.A., Chudakov D.M., Gorodnicheva T.V., Lukyanov S., Lukyanov K.A. (2009). Cell culture medium affects GFP photostability: a solution. Nat. Methods 6 (12), 859–60
  3. Bogdanov A.M., Mishin A.S., Yampolsky I.V., Belousov V.V., Chudakov D.M., Subach F.V., Verkhusha V.V., Lukyanov S., Lukyanov K.A. (2009). Green fluorescent proteins are light-induced electron donors. Nat. Chem. Biol.  (5), 459–461 [+]

    Proteins of the green fluorescent protein (GFP) family are well known owing to their unique biochemistry and extensive use as in vivo markers. We discovered that GFPs of diverse origins can act as light-induced electron donors in photochemical reactions with various electron acceptors, including biologically relevant ones. Moreover, via green-to-red GFP photoconversion, this process can be observed in living cells without additional treatment.

  4. Shcherbo D., Murphy C.S., Ermakova G.V., Solovieva E.A., Chepurnykh T.V., Shcheglov A.S., Verkhusha V.V., Pletnev V.Z., Hazelwood K.L., Roche P.M., Lukyanov S., Zaraisky A.G., Davidson M.W., Chudakov D.M. (2009). Far-red fluorescent tags for protein imaging in living tissues. Biochem. J. 418 (3), 567–74 [+]

    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.

  5. Shcherbo D., Merzlyak E.M., Chepurnykh T.V., Fradkov A.F., Ermakova G.V., Solovieva E.A., Lukyanov K.A., Bogdanova E.A., Zaraisky A.G., Lukyanov S., Chudakov D.M. (2007). Bright far-red fluorescent protein for whole-body imaging. Nat. Methods 4 (9), 741–6 [+]

    A novel fluorescent protein Katushka with far-red emission preferable for signal registration inside animal tissues was created. Katushka is 10 fold brighter than other far-red proteins and is also characterized with fast maturation, high pH-stability and photostability. This constellation of properties makes it an instrument of choice for in vivo labeling of particular cells within whole organisms. A monomeric variant of Katushka named mKate was introduced for intracellular protein localization studies.

  6. Merzlyak E.M., Goedhart J., Shcherbo D., Bulina M.E., Shcheglov A.S., Fradkov A.F., Gaintzeva A., Lukyanov K.A., Lukyanov S., Gadella T.W., Chudakov D.M. (2007). Bright monomeric red fluorescent protein with an extended fluorescence lifetime. Nat. Methods 4 (7), 555–7 [+]

    Fluorescent proteins have become extremely popular tools for in vivo imaging and especially for the study of localization, motility and interaction of proteins in living cells. Here we report TagRFP, a monomeric red fluorescent protein, which is characterized by high brightness, complete chromophore maturation, prolonged fluorescence lifetime and high pH-stability. These properties make TagRFP an excellent tag for protein localization studies and fluorescence resonance energy transfer (FRET) applications.

  7. Chudakov D.M., Lukyanov S., Lukyanov K.A. (2007). Using photoactivatable fluorescent protein Dendra2 to track protein movement. BioTechniques 42 (5), 553, 555, 557 passim [+]

    Photoactivatable fluorescent proteins are capable of dramatic changes in fluorescent properties in response to specific light irradiation. For example, they can be converted from cyan to green, or from green to red, or from nonfluorescent to a brightly fluorescent state. Several types of such proteins were developed recently, and some of them are already becoming popular tools to study protein mobility. Here we provide detailed recommendations on application of the monomeric green-to-red photoconvertible fluorescent protein Dendra2 for protein tracking in living cultured cells.

  8. Chudakov D.M., Chepurnykh T.V., Belousov V.V., Lukyanov S., Lukyanov K.A. (2006). Fast and precise protein tracking using repeated reversible photoactivation. Traffic 7 (10), 1304–10 [+]

    Photoactivatable fluorescent proteins opened principally novel possibilities to study proteins' movement pathways. In particular, reversibly photoactivatable proteins enable multiple tracking experiments in a long-drawn work with a single cell. Here we report 'protein rivers tracking' technique based on repeated identical rounds of photoactivation and subsequent images averaging, which results in dramatic increase of imaging resolution for fast protein movement events.

  9. Belousov V.V., Fradkov A.F., Lukyanov K.A., Staroverov D.B., Shakhbazov K.S., Terskikh A.V., Lukyanov S. (2006). Genetically encoded fluorescent indicator for intracellular hydrogen peroxide. Nat. Methods 3 (4), 281–6 [+]

    A unique fluorescent sensor HyPer was introduced for in vivo monitoring of concentration of hydrogen peroxide — one of the major regulators of biological processes. Being a protein, HyPer can be expressed in cells or targeted specifically to a particular cell compartment. Due to its high specificity and sensitivity HyPer can be used for monitoring fluctuations of hydrogen peroxide concentration in a single cell or cell organelle.

  10. Gurskaya N.G., Verkhusha V.V., Shcheglov A.S., Staroverov D.B., Chepurnykh T.V., Fradkov A.F., Lukyanov S., Lukyanov K.A. (2006). Engineering of a monomeric green-to-red photoactivatable fluorescent protein induced by blue light. Nat. Biotechnol. 24 (4), 461–5 [+]

    A novel monomeric fluorescent protein Dendra was developed, which is capable of irreversible photoconversion from a green fluorescent form into a red fluorescent one. Dendra is bright and can be activated with either UV or blue light.

  11. Bulina M.E., Lukyanov K.A., Britanova O.V., Onichtchouk D., Lukyanov S., Chudakov D.M. (2006). Chromophore-assisted light inactivation (CALI) using the phototoxic fluorescent protein KillerRed. Nat Protoc 1 (2), 947–53 [+]

    The phototoxic red fluorescent GFP-like protein KillerRed has recently been described. The phototoxicity of KillerRed exceeds that of EGFP by at least 1,000-fold, making it the first fully genetically encoded photosensitizer. KillerRed opens up new possibilities for precise light-induced cell killing and target protein inactivation. Because KillerRed is encoded by a gene, it can be expressed in a spatially and temporally regulated manner, under a chosen promoter, and fused with the desired protein of interest or localization signal. Here we provide a protocol for target protein inactivation in cell culture using KillerRed. As KillerRed is a new tool, the protocol focuses on aspects that will allow users to maximize the potential of this protein, guiding the design of chimeric constructs, recommended control experiments and preferred illumination parameters. The protocol, which describes target protein visualization and subsequent inactivation, is a 2- or 3-d procedure.

  12. Bulina M.E., Chudakov D.M., Britanova O.V., Yanushevich Y.G., Staroverov D.B., Chepurnykh T.V., Merzlyak E.M., Shkrob M.A., Lukyanov S., Lukyanov K.A. (2006). A genetically encoded photosensitizer. Nat. Biotechnol. 24 (1), 95–9 [+]

    Photosensitizers are chromophores that generate reactive oxygen species (ROS) upon light irradiation. They are used for inactivation of specific proteins by chromophore-assisted light inactivation (CALI) and for light-induced cell killing in photodynamic therapy. Here we report a genetically encoded photosensitizer, which we call KillerRed, developed from the hydrozoan chromoprotein anm2CP, a homolog of green fluorescent protein (GFP). KillerRed generates ROS upon irradiation with green light. Whereas known photosensitizers must be added to living systems exogenously, KillerRed is fully genetically encoded. We demonstrate the utility of KillerRed for light-induced killing of Escherichia coli and eukaryotic cells and for inactivating fusions to beta-galactosidase and phospholipase Cdelta1 pleckstrin homology domain.

  13. Lukyanov K.A., Chudakov D.M., Fradkov A.F., Labas Y.A., Matz M.V., Lukyanov S. (2006). Discovery and properties of GFP-like proteins from nonbioluminescent anthozoa. Methods Biochem Anal 47, 121–38
  14. Shkrob M.A., Yanushevich Y.G., Chudakov D.M., Gurskaya N.G., Labas Y.A., Poponov S.Y., Mudrik N.N., Lukyanov S., Lukyanov K.A. (2005). Far-red fluorescent proteins evolved from a blue chromoprotein from Actinia equina. Biochem. J. 392 (Pt 3), 649–54 [+]

    Proteins of the GFP (green fluorescent protein) family demonstrate a great spectral and phylogenetic diversity. However, there is still an intense demand for red-shifted GFP-like proteins in both basic and applied science. To obtain GFP-like chromoproteins with red-shifted absorption, we performed a broad search in blue-coloured Anthozoa species. We revealed specimens of Actinia equina (beadlet anemone) exhibiting a bright blue circle band at the edge of the basal disc. A novel blue chromoprotein, aeCP597, with an absorption maximum at 597 nm determining the coloration of the anemone basal disk was cloned. AeCP597 carries a chromophore chemically identical with that of the well-studied DsRed (red fluorescent protein from Discosoma sp.). Thus a strong 42-nm bathochromic shift of aeCP597 absorption compared with DsRed is determined by peculiarities of chromophore environment. Site-directed and random mutagenesis of aeCP597 resulted in far-red fluorescent mutants with emission maxima at up to 663 nm. The most bright and stable mutant AQ143 possessed excitation and emission maxima at 595 and 655 nm respectively. Thus aeCP597 and its fluorescent mutants set a new record of red-shifted absorption and emission maxima among GFP-like proteins.

  15. Chudakov D.M., Lukyanov S., Lukyanov K.A. (2005). Fluorescent proteins as a toolkit for in vivo imaging. Trends Biotechnol. 23 (12), 605–13 [+]

    Green fluorescent protein (GFP) from the jellyfish Aequorea victoria, and its mutant variants, are the only fully genetically encoded fluorescent probes available and they have proved to be excellent tools for labeling living specimens. Since 1999, numerous GFP homologues have been discovered in Anthozoa, Hydrozoa and Copepoda species, demonstrating the broad evolutionary and spectral diversity of this protein family. Mutagenic studies gave rise to diversified and optimized variants of fluorescent proteins, which have never been encountered in nature. This article gives an overview of the GFP-like proteins developed to date and their most common applications to study living specimens using fluorescence microscopy.

  16. Lukyanov K.A., Chudakov D.M., Lukyanov S., Verkhusha V.V. (2005). Innovation: Photoactivatable fluorescent proteins. Nat. Rev. Mol. Cell Biol. 6 (11), 885–91 [+]

    The fluorescence characteristics of photoactivatable proteins can be controlled by irradiating them with light of a specific wavelength, intensity and duration. This provides unique possibilities for the optical labelling and tracking of living cells, organelles and intracellular molecules in a spatio-temporal manner. Here, we discuss the properties of the available photoactivatable fluorescent proteins and their potential applications.

  17. Chudakov D.M., Verkhusha V.V., Staroverov D.B., Souslova E.A., Lukyanov S., Lukyanov K.A. (2004). Photoswitchable cyan fluorescent protein for protein tracking. Nat. Biotechnol. 22 (11), 1435–9 [+]

    In recent years diverse photolabeling techniques using green fluorescent protein (GFP)-like proteins have been reported, including photoactivatable PA-GFP, photoactivatable protein Kaede, the DsRed 'greening' technique and kindling fluorescent proteins. So far, only PA-GFP, which is monomeric and gives 100-fold fluorescence contrast, could be applied for protein tracking. Here we describe a dual-color monomeric protein, photoswitchable cyan fluorescent protein (PS-CFP). PS-CFP is capable of efficient photoconversion from cyan to green, changing both its excitation and emission spectra in response to 405-nm light irradiation. Complete photoactivation of PS-CFP results in a 1,500-fold increase in the green-to-cyan fluorescence ratio, making it the highest-contrast monomeric photoactivatable fluorescent protein described to date. We used PS-CFP as a photoswitchable tag to study trafficking of human dopamine transporter in living cells. At moderate excitation intensities, PS-CFP can be used as a pH-stable cyan label for protein tagging and fluorescence resonance energy transfer applications.

  18. Bulina M.E., Lukyanov K.A., Yampolsky I.V., Chudakov D.M., Staroverov D.B., Shcheglov A.S., Gurskaya N.G., Lukyanov S. (2004). New class of blue animal pigments based on Frizzled and Kringle protein domains. J. Biol. Chem. 279 (42), 43367–70 [+]

    The nature of coloration in many marine animals remains poorly investigated. Here we studied the blue pigment of a scyfoid jellyfish Rhizostoma pulmo and determined it to be a soluble extracellular 30-kDa chromoprotein with a complex absorption spectrum peaking at 420, 588, and 624 nm. Furthermore, we cloned the corresponding cDNA and confirmed its identity by immunoblotting and mass spectrometry experiments. The chromoprotein, named rpulFKz1, consists of two domains, a Frizzled cysteine-rich domain and a Kringle domain, inserted into one another. Generally, Frizzleds are members of a basic Wnt signal transduction pathway investigated intensely with regard to development and cancerogenesis. Kringles are autonomous structural domains found throughout the blood clotting and fibrinolytic proteins. Neither Frizzled and Kringle domains association with any type of coloration nor Kringle intrusion into Frizzled sequence was ever observed. Thus, rpulFKz1 represents a new class of animal pigments, whose chromogenic group remains undetermined. The striking homology between a chromoprotein and members of the signal transduction pathway provides a novel node in the evolution track of growth factor-mediated morphogenesis compounds.

  19. Verkhusha V.V., Chudakov D.M., Gurskaya N.G., Lukyanov S., Lukyanov K.A. (2004). Common pathway for the red chromophore formation in fluorescent proteins and chromoproteins. Chem. Biol. 11 (6), 845–54 [+]

    The mechanism of the chromophore maturation in members of the green fluorescent protein (GFP) family such as DsRed and other red fluorescent and chromoproteins was analyzed. The analysis indicates that the red chromophore results from a chemical transformation of the protonated form of the GFP-like chromophore, not from the anionic form, which appears to be a dead-end product. The data suggest a rational strategy to achieve the complete red chromophore maturation utilizing substitutions to favor the formation of the neutral phenol in GFP-like chromophore. Our approach to detect the neutral chromophore form expands the application of fluorescent timer proteins to faster promoter activities and more spectrally distinguishable fluorescent colors. Light sensitivity found in the DsRed neutral form, resulting in its instant transformation to the mature red chromophore, could be exploited to accelerate the fluorescence acquisition.

  20. Chudakov D.M., Feofanov A.V., Mudrik N.N., Lukyanov S., Lukyanov K.A. (2003). Chromophore environment provides clue to "kindling fluorescent protein" riddle. J. Biol. Chem. 278 (9), 7215–9 [+]

    asCP, the unique green fluorescent protein-like nonfluorescent chromoprotein from the sea anemone Anemonia sulcata, becomes fluorescent ("kindles") upon green light irradiation, with maximum emission at 595 nm. The kindled protein then relaxes to a nonfluorescent state or can be "quenched" instantly by blue light irradiation. In this work, we used asCP mutants to investigate the mechanism underlying kindling. Using site-directed mutagenesis we showed that amino acids spatially surrounding Tyr(66) in the chromophore are crucial for kindling. We propose a model of the kindling mechanism, in which the key event is chromophore turning or cis-trans isomerization. Using site-directed mutagenesis we also managed to transfer the kindling property to the two other coral chromoproteins. Remarkably, most kindling mutants were capable of both reversible and irreversible kindling. Also, we obtained novel variants that kindled upon blue light irradiation. The diversity of photoactivated fluorescent proteins that can be developed by site-directed mutagenesis is promising for biotechnological needs.

  21. Chudakov D.M., Belousov V.V., Zaraisky A.G., Novoselov V.V., Staroverov D.B., Zorov D.B., Lukyanov S., Lukyanov K.A. (2003). Kindling fluorescent proteins for precise in vivo photolabeling. Nat. Biotechnol. 21 (2), 191–4 [+]

    Photobleaching of green fluorescent protein (GFP) is a widely used approach for tracking the movement of subcellular structures and intracellular proteins. Although photobleaching is a powerful technique, it does not allow direct tracking of an object's movement and velocity within a living cell. Direct tracking becomes possible only with the introduction of a photoactivated fluorescent marker. A number of previous studies have reported optically induced changes in the emission spectra of fluorescent proteins. However, the ideal photoactivated fluorescent marker should be a nonfluorescent tag capable of "switching on" (i.e., becoming fluorescent) in response to irradiation by light of a particular wavelength, intensity, and duration. In this report, we generated a mutant of Anemonia sulcata chromoprotein asCP. The mutant protein is capable of unique irreversible photoconversion from the nonfluorescent to a stable bright-red fluorescent form ("kindling"). This "kindling fluorescent protein" (KFP1) can be used for precise in vivo photolabeling to track the movements of cells, organelles, and proteins. We used KFP1 for in vivo cell labeling in mRNA microinjection assays to monitor Xenopus laevis embryo development and to track mitochondrial movement in mammalian cells.

  22. Shagin D.A., Rebrikov D.V., Kozhemyako V.B., Altshuler I.M., Shcheglov A.S., Zhulidov P.A., Bogdanova E.A., Staroverov D.B., Rasskazov V.A., Lukyanov S. (2002). A novel method for SNP detection using a new duplex-specific nuclease from crab hepatopancreas. Genome Res. 12 (12), 1935–42 [+]

    A new enzyme — Duplex-Specific Nuclease from Camchatka crab hepatopancreas — was found and characterized. DSN is highly specific to double-strand DNA and exhibits no activity against single-strand DNA and RNA in a wide temperature range. Its unique properties make it a perfect tool for eliminating double-strand DNA from complex mixtures of nucleic acids.

  23. Terskikh A., Fradkov A., Ermakova G., Zaraisky A., Tan P., Kajava A.V., Zhao X., Lukyanov S., Matz M., Kim S., Weissman I., Siebert P. (2000). "Fluorescent timer": protein that changes color with time. Science 290 (5496), 1585–8 [+]

    We generated a mutant of the red fluorescent protein drFP583. The mutant (E5) changes its fluorescence from green to red over time. The rate of color conversion is independent of protein concentration and therefore can be used to trace time-dependent expression. We used in vivo labeling with E5 to measure expression from the heat shock-dependent promoter in Caenorhabditis elegans and from the Otx-2 promoter in developing Xenopus embryos. Thus, E5 is a "fluorescent timer" that can be used to monitor both activation and down-regulation of target promoters on the whole-organism scale.

  24. Matz M.V., Fradkov A.F., Labas Y.A., Savitsky A.P., Zaraisky A.G., Markelov M.L., Lukyanov S.A. (1999). Fluorescent proteins from nonbioluminescent Anthozoa species. Nat. Biotechnol. 17 (10), 969–73 [+]

    Novel fluorescent proteins with different fluorescence colors from blue to red were found in Anthozoa species. Discovery of chromo- and fluorescent GFP-like proteins in non-bioluminescent coral polyps disproved the common belief, that these proteins are obligatory attached to bioluminescense systems and disclosed the nature of fluorescent coloration of corals — a phenomenon, that didn’t have proper explanation before.

  25. Kazanskaya O.V., Severtzova E.A., Barth K.A., Ermakova G.V., Lukyanov S.A., Benyumov A.O., Pannese M., Boncinelli E., Wilson S.W., Zaraisky A.G. (1997). Anf: a novel class of vertebrate homeobox genes expressed at the anterior end of the main embryonic axis. Gene 200 (1-2), 25–34 [+]

    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.

  26. Zaraisky A.G., Ecochard V., Kazanskaya O.V., Lukyanov S.A., Fesenko I.V., Duprat A.M. (1995). The homeobox-containing gene XANF-1 may control development of the Spemann organizer. Development 121 (11), 3839–47 [+]

    At the beginning of gastrulation the homeobox-containing gene, XANF-1, is expressed at a low level throughout the animal hemisphere of Xenopus laevis embryos, with a local maximum of expression in the region of the dorsal blastopore lip. By the end of gastrulation expression ceases everywhere except in the most anterior part of the neurectoderm. We have investigated the functions of this gene by microinjecting XANF-1 mRNA in the blastomeres of the 32-cell stage embryo and have observed the following effects. First, microinjections of the mRNA in the animal blastomeres and the blastomeres of the marginal zone elicited massive migration of cells to the interior of the embryo at the early gastrula stage. Second, overexpression of XANF-1 in the ventral marginal zone (VMZ) resulted in the appearance of an additional centre of gastrulation movements and the formation of a secondary axis. In addition we showed that synthetic XANF-1 mRNA was able to cause dorsal-type differentiation in VMZ explants extirpated from the microinjected embryos at the beginning of gastrulation. These results suggest that XANF-1 may control the main functions of cells of the Spemann organizer.

  27. Zaraisky A.G., Lukyanov S.A., Vasiliev O.L., Smirnov Y.V., Belyavsky A.V., Kazanskaya O.V. (1992). A novel homeobox gene expressed in the anterior neural plate of the Xenopus embryo. Dev. Biol. 152 (2), 373–82 [+]

    To obtain gene sequences controlling the early steps of amphibian neurogenesis, we have performed differential screening of a subtractive cDNA library prepared by a novel PCR-based method from a single presumptive neural plate of a Xenopus laevis late-gastrula embryo. As a result we have isolated a fragment of a novel homeobox gene (named XANF-1, for Xenopus anterior neural folds). This gene is expressed predominantly in the anterior part of the developing nervous system. Such preferential localization of XANF-1 mRNA is established from its initially homogenous distribution in ectoderm of early gastrula. This change in the expression pattern is conditioned by a differential influence of various mesoderm regions on ectoderm: anterior mesoderm activates XANF-1 expression in the overlying ectoderm, whereas posterior axial and ventral mesoderm areas inhibit it. The data obtained demonstrate for the first time that selection of genes for specific expression in the CNS of the early vertebrate embryo is affected not only by chordamesoderm (a neural inductor) but also by ventral mesoderm.