Villo Muha

Publications (3)8.76 Total impact

• Article: Association of RNA with the uracil-DNA-degrading factor has major conformational effects and is potentially involved in protein folding.

  Angela Bekesi, Maria Pukancsik, Peter Haasz, Lilla Felfoldi, Ibolya Leveles, Villo Muha, Eva Hunyadi-Gulyas, Anna Erdei, Katalin F Medzihradszky, Beata G Vertessy
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  ABSTRACT: Recently, a novel uracil-DNA-degrading factor protein (UDE) was identified in Drosophila melanogaster, with homologues only in pupating insects. Its unique uracil-DNA-degrading activity and a potential domain organization pattern have been described. UDE seems to be the first representative of a new protein family with unique enzyme activity that has a putative role in insect development. In addition, UDE may also serve as potential tool in molecular biological applications. Owing to lack of homology with other proteins with known structure and/or function, de novo data are required for a detailed characterization of UDE structure and function. Here, experimental evidence is provided that recombinant protein is present in two distinct conformers. One of these contains a significant amount of RNA strongly bound to the protein, influencing its conformation. Detailed biophysical characterization of the two distinct conformational states (termed UDE and RNA-UDE) revealed essential differences. UDE cannot be converted into RNA-UDE by addition of the same RNA, implying putatively joint processes of RNA binding and protein folding in this conformational species. By real-time PCR and sequencing after random cloning, the bound RNA pool was shown to consist of UDE mRNA and the two ribosomal RNAs, also suggesting cotranslational RNA-assisted folding. This finding, on the one hand, might open a way to obtain a conformationally homogeneous UDE preparation, promoting successful crystallization; on the other hand, it might imply a further molecular function of the protein. In fact, RNA-dependent complexation of UDE was also demonstrated in a fruit fly pupal extract, suggesting physiological relevance of RNA binding of this DNA-processing enzyme.
  FEBS Journal 01/2011; 278(2):295-315. · 3.79 Impact Factor
• Article: Nuclear localization signal-dependent and -independent movements of Drosophila melanogaster dUTPase isoforms during nuclear cleavage.

  Villo Muha, Imre Zagyva, Zsolt Venkei, János Szabad, Beáta G Vértessy
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  ABSTRACT: Two dUTPase isoforms (23 kDa and 21 kDa) are present in the fruitfly with the sole difference of an N-terminal extension. In Drosophila embryo, both isoforms are detected inside the nucleus. Here, we investigated the function of the N-terminal segment using eYFP-dUTPase constructs. In Schneider 2 cells, only the 23 kDa construct showed nuclear localization arguing that it may contain a nuclear localization signal (NLS). Sequence comparisons identified a lysine-rich nonapeptide with similarity to the human c-myc NLS. In Drosophila embryos during nuclear cleavages, the 23 kDa isoform showed the expected localization shifts. Contrariwise, although the 21 kDa isoform was excluded from the nuclei during interphase, it was shifted to the nucleus during prophase and forthcoming mitotic steps. The observed dynamic localization character showed strict timing to the nuclear cleavage phases and explained how both isoforms can be present within the nuclear microenvironment, although at different stages of cell cycle.
  Biochemical and Biophysical Research Communications 03/2009; 381(2):271-5. · 2.48 Impact Factor
• Source

  Available from: Beáta G Vértessy

  Article: A novel fruitfly protein under developmental control degrades uracil-DNA.

  Angéla Békési, Mária Pukáncsik, Villo Muha, Imre Zagyva, Ibolya Leveles, Eva Hunyadi-Gulyás, Eva Klement, Katalin F Medzihradszky, Zoltán Kele, Anna Erdei, Ferenc Felföldi, Emese Kónya, Beáta G Vértessy
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  ABSTRACT: Uracil in DNA may arise by cytosine deamination or thymine replacement and is removed during DNA repair. Fruitfly larvae lack two repair enzymes, the major uracil-DNA glycosylase and dUTPase, and may accumulate uracil-DNA. We asked if larval tissues contain proteins that specifically recognize uracil-DNA. We show that the best hit of pull-down on uracil-DNA is the protein product of the Drosophila melanogaster gene CG18410. This protein binds to both uracil-DNA and normal DNA but degrades only uracil-DNA; it is termed Uracil-DNA Degrading Factor (UDE). The protein has detectable homology only to a group of sequences present in genomes of pupating insects. It is under detection level in the embryo, most of the larval stages and in the imago, but is strongly upregulated right before pupation. In Schneider 2 cells, UDE mRNA is upregulated by ecdysone. UDE represents a new class of proteins that process uracil-DNA with potential involvement in metamorphosis.
  Biochemical and Biophysical Research Communications 05/2007; 355(3):643-8. · 2.48 Impact Factor