Plant Molecular Biology - Karel Říha

Research areas

• Telomeres and genome stability
• Regulation of meiosis
• Role of RNA decay in genome regulation

Main objectives

• Deciphering mechanisms of chromosome end protection
• Understanding regulatory pathways that define the meiotic mode of chromosome segregation and application of this knowledge in plant breeding
• Investigating non-canonical functions of the proteins involved in nonsense mediated RNA decay  

Content of research

We study processes governing genome stability and chromosome segregation. Our research aims to decipher the molecular mechanisms that stabilize and protect chromosome ends, called telomeres, from being perceived by the cell as DNA damage. We also investigate the regulatory pathways that define meiosis, the cell division necessary for sexual reproduction and the generation of haploid gametes.

Telomeres form the ends of eukaryotic chromosomes and are important for the complete replication of linear genomes and for chromosome stability. We found that the opposite ends of a chromosome adopt different end protective structures, the formation of which is dictated by the mode of DNA replication. Furthermore, we discovered a fundamentally novel mechanism of chromosome end protection that relies on the evolutionary conserved DNA repair complex Ku. In our current research we aim to understand how Ku mediates protection of these telomeres without triggering a DNA repair reaction. In our meiotic research we aim to delineate pathways involved in remodelling of the cell cycle machinery to enable the meiotic mode of chromosome segregation. We have identified Arabidopsis meiotic cyclins and revealed their contribution to diverse meiotic processes. Furthermore, we have discovered a genetic module, consisting of SMG7 and TDM1 that inhibits meiotic CDKs and facilitates the transition from meiosis to mitosis. Our current work is directed towards a molecular understanding of the SMG7/TDM1 function and characterization of additional genes involved in meiotic progression.

list / cards

SELECTED PUBLICATIONS

2017

• VALUCHOVA, S; FULNECEK, J; PROKOP, Z; STOLT-BERGNER, P; JANOUSKOVA, E; HOFR, C; RIHA, K, 2017:Protection of Arabidopsis Blunt-Ended Telomeres Is Mediated by a Physical Association with the Ku Heterodimer. PLANT CELL 29 (6), p. 1533 - 1545.

2016

• CIFUENTES, M; JOLIVET, S; CROMER, L; HARASHIMA, H; BULANKOVA, P; RENNE, C; CRISMANI, W; NOMURA, Y; NAKAGAMI, H; SUGIMOTO, K; SCHNITTGER, A; RIHA, K; MERCIER, R, 2016:TDM1 Regulation Determines the Number of Meiotic Divisions. PLOS GENETICS 12 (2)
• RAXWAL, VK; RIHA, K, 2016:Nonsense mediated RNA decay and evolutionary capacitance. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 1859 (12), p. 1538 - 1543.

2015

• FULCHER, N; TEUBENBACHER, A; KERDAFFREC, E; FARLOW, A; NORDBORG, M; RIHA, K, 2015:Genetic Architecture of Natural Variation of Telomere Length in Arabidopsis thaliana. GENETICS 199 (2), p. 625 - 635.
• SINHA, S; RAXWAL, VK; JOSHI, B; JAGANNATH, A; KATIYAR-AGARWAL, S; GOEL, S; KUMAR, A; AGARWAL, M, 2015:De novo transcriptome profiling of cold-stressed siliques during pod filling stages in Indian mustard (Brassica juncea L.). FRONTIERS IN PLANT SCIENCE 6

2014

• DERBOVEN, E; EKKER, H; KUSENDA, B; BULANKOVA, P; RIHA, K, 2014:Role of STN1 and DNA Polymerase alpha in Telomere Stability and Genome-Wide Replication in Arabidopsis. PLOS GENETICS 10 (10)
• GLOGGNITZER, J; AKIMCHEVA, S; SRINIVASAN, A; KUSENDA, B; RIEHS, N; STAMPFL, H; BAUTOR, J; DEKROUT, B; JONAK, C; JIMENEZ-GOMEZ, JM; PARKER, JE; RIHA, K, 2014:Nonsense-Mediated mRNA Decay Modulates Immune Receptor Levels to Regulate Plant Antibacterial Defense. CELL HOST & MICROBE 16 (3), p. 376 - 390.
• PLECENIKOVA, A; SLANINOVA, M; RIHA, K, 2014:Characterization of DNA Repair Deficient Strains of Chlamydomonas reinhardtii Generated by Insertional Mutagenesis. PLOS ONE 9 (8)

2010

• BULANKOVA, P; RIEHS-KEARNAN, N; NOWACK, MK; SCHNITTGER, A; RIHA, K, 2010:Meiotic Progression in Arabidopsis Is Governed by Complex Regulatory Interactions between SMG7, TDM1, and the Meiosis I-Specific Cyclin TAM. PLANT CELL 22 (11), p. 3791 - 3803.

1. Discovery of genes governing differentiation of plant germline

Supervisor: Mgr. Karel Říha, Ph.D.

Annotation:

Analyzing various aspects of germ-line differentiation.

Keywords: plant germ-line

2. Mechanisms controlling germ-line differentiation in plants

Supervisor: Mgr. Karel Říha, Ph.D.

Plant germ-line forms during late stages of plant growth within developing floral organs. We use genetic, cell biology and biochemical tools delineate molecular processes that govern formation of haploid gametophytes from diploid precursors. We are particularly interested in mechanisms that regulate meiosis. We have designed a genetic screen to identify novel genes involved meiotic progression in Arabidopsis thaliana. The PhD project deals with functional characterization of the genes discovered in the screen and  development of technologies for in depth analysis of plant germ-line differentiation.

Keywords: plant germ-line