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Inherited Diseases II – Transcriptional Regulation

Mgr. Dalibor Blažek, Ph.D.
Research Group Leader

Email contact: dblazek@med.muni.cz

THEMATIC RESEARCH FOCUS

RESEARCH AREAS

  • Regulation of eukaryotic transcription
  • Role of Cdk9, Cdk12 and Cdk13 in regulation of gene expression
  • Role of transcription cycle-related Cdks in maintenance of genome stability
  • Transcription cycle-related Cdks in human disease

MAIN OBJECTIVES

  • Role of Cdks in phosphorylation of the C-terminal domain of RNA polymerase II and in the regulation of gene expression
  • Control of DNA damage response and genome stability via regulation of expression of DNA damage response genes

CONTENT OF RESEARCH

RNA polymerase II (RNAPII) directs transcription of protein coding genes and this process consists of several stages including preinitiation complex formation, productive elongation and termination. This transcription cycle is tightly linked to co-transcriptional maturation of nascent transcripts including pre-mRNA splicing and polyadenylation. RNAPII contains an unstructured C-terminal domain (CTD) with repeats of evolutionarily conserved heptapeptide YSPTSPS, where individual serines get phosphorylated. Several cyclin-dependent kinases (Cdks) regulate the phosphorylation status of the CTD and subsequent binding of transcription and pre-mRNA processing factors. Thus, the patterns of phosphorylation of the CTD direct actions of RNAPII during transcriptional cycle and co-transcriptional processing of nascent transcripts. Moreover, CTD was also functionally linked to DNA damage response and maintenance of genome stability via regulation of transcription, mRNA processing and recombination. Thus, CTD and its posttranslational modifications, associated proteins and modifying enzymes are emerging as new players in cellular response to DNA damage. Our recent work led to the identification of the Cyclin K/Cdk12 complex that phosphorylates serine 2 in the CTD of RNAPII and directs expression of several crucial DNA damage response genes including BRCA1, ATR or FANCI. In my lab we apply a combination of biochemical, proteomics and genome-wide techniques to determine the molecular mechanism that regulates the expression of Cdk12-dependent genes with a focus on DNA damage response genes. The ultimate goal of our research is to uncover how the CycK/Cdk12 complex and the CTD of RNAPII contribute to the maintenance of genome stability, and how disruption of their functions lead to the onset of a malignant state. 

PEOPLE

Mgr. Dalibor Blazek, Ph.D. – principal investigator

Mgr. Pavla Gajduskova, Ph.D. - research assistant

Mgr. Jana Rybarikova, Ph.D. – postdoc

KEY RESEARCH EQUIPMENT

PLANNED RESEARCH INFRASTRUCTURE

Core Facility

The research group will be one of the principal users of the equipment available within CEITEC Genomics Core Facility.

CURRENT RESEARCH INFRASTRUCTURE

Laboratories equipped with technologies used in molecular biological analysis: RealTime PCR cyclers, PCR cyclers, laminar boxes, CO2 boxes.

MAIN PROJECTS

  • The novel isoform of cyclin K is a partner of cdk12 kinase regulating eukaryotic transcription and alternative splicing (GAP305/11/1564), Czech Science Foundation, 2011-2013, Dalibor Blažek, Masaryk University.
  • Novel methylation of Hexim1 and cyclin composition of positive trancription elongation factor b (P-TEFb) regulate kinase activity of cdk9 (ME09047), Ministry of Education, Youth and Sports, 2009-2013, Dalibor Blažek, University Hospital Brno.
  • Regulation and function of P-TEFb complexes (SRGA 454), 35 months, SoMoPro Reintegration Grant, Dalibor Blažek, Masaryk University.

SELECTED PUBLICATIONS

  1. Kohoutek J., Blazek D.*: Cyclin K goes with Cdk12 and Cdk13. Cell Division. In press. (2012). Invited review
  2. Blazek D.*: The Cyclin K/Cdk12 complex: An emerging new player in the maintenance of genome stability. Cell Cycle 11 (6): 1049-1050 (2012). Invited “Feature article”
  3. Blazek D.*, Kohoutek J., Bartholomeeusen K., Johansen E., Hulinkova P., Luo Z., Cimermancic P.,Ule J., Peterlin B.M.: The CycK/Cdk12 complex maintains genomic stability via regulation of expression of DNA damage response genes. Genes and Development  25 (20): 2158-2172 (2011).
  4. Kohoutek J., Li Q., Blazek D., Luo Z., Jiang H., Peterlin B.M.: Cyclin T2 is essential for Mouse Embryogenesis. Molecular and Cellular Biology 29 (12) 3280-3285 (2009).
  5. Blazek D., Peterlin B.M.: Tat-SIRT1 Tango. Molecular Cell 29 (5), 539-540 (2008). Preview.
  6. Kohoutek J., Blazek D., Peterlin B.M.: HEXIM1 Sequesters Positive Transcription Elongation Factor b from the Class II Transactivator on MHC Class II Promoters. Proc Natl Acad Sci USA 103 (46), 17349-54 (2006).
  7. Blazek D., Barboric M., Kohoutek J., Oven I., Peterlin B.M.: Oligomerization of HEXIM1 via 7SK snRNA and Coiled-coil region Directs the Inhibition of P-TEFb. Nucleic Acids Research 33 (22), 7000-7010 (2005).
  8. Barboric M., Kohoutek J., Price J.P., Blazek D., Price D.H., Peterlin B.M.: Interplay between 7SK snRNA and Oppositely Charged Regions in HEXIM1 Direct the Inhibition of P-TEFb. EMBO Journal 24(24), 4291-4303 (2005).
  9. Schulte A., Czudnochowski N., Barboric M., Schoninchen A., Blazek D., Peterlin B.M., Geyer M.: Identification of Cyclin T-binding Domain in HEXIM1 and Biochemical Analysis of its Binding Competition with HIV-1 Tat. Journal of Biological Chemistry 280 (26), 24968-24977 (2005).
  10. Blazek D.*, Celer V., Navratilova I., Skladal P.: Generation and Characterization of Single-chain Antibody Fragments Specific against Transmembrane Envelope Glycoprotein gp46 of Maedi-visna Virus. Journal of Virological Methods 115 (1), 83-92 (2004).

*Corresponding author

 

 

 

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