Pr. Martin Teichmann

Professor (Pr1), Université Bordeaux Segalen

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Website

Tel: +33(0)540003053

Bio

Born in Göttingen, Germany, Martin Teichmann studied Medicine at the Universities of Marburg and Heidelberg, Germany, where he obtained a medical degree in 1992. In 1996, he completed his doctoral work in Molecular Biology under the supervision of Prof. Klaus H. Seifart at the Institute for Molecular Biology and Tumor Research in Marburg. In 1997, he joined Prof. Robert G. Roeder’s laboratory at The Rockefeller University in New York / United States as a Postdoctoral Fellow. He was promoted to Research Associate in 2000. He was appointed Group Leader at the IECB in 2002.

Keywords / Expertise / Techniques

RNA polymerase, transcription, cellular transformation, interfering RNA, gene regulation, in vitro transcription, two-hybrid screen, generation of stable mammalian cell lines, northern-blot, protein purification (LC, FPLC), western-blot, 2D gel-electrophoresis, EMSA, DNA footprint

Summary

We study the regulation of human RNA polymerase III (Pol III) transcription with a focus on understanding how Pol III transcription escapes cellular control mechanisms during tumor development. Recently, we identified and characterized a novel isoform of human RNA polymerase III (Pol IIIa and Pol IIIb). RPC32a-containing Pol IIIa is highly expressed in undifferentiated human embryonic stem cells, downregulated during differentiation and reactivated during the process of cell transformation with defined genetic elements. In contrast, the expression of RPC32b-containing Pol IIIb is not regulated during these processes. Moreover, expression of RPC32a is important for cell transformation and anchorage- independent growth. We now try to elucidate how Pol IIIa contributes to cellular transformation.

Activity report

Transcription in eukaryotic nuclei is carried out by DNA-dependent RNA polymerases I, II, and III. Human RNA polymerase III (Pol III) transcribes small untranslated RNAs that include tRNAs, 5S RNA, U6 RNA, and some microRNAs. Increased Pol III transcription has been reported to accompany or cause cell transformation. We try to shed light on mechanisms that underlie the control of Pol III transcription in normal cells and that are lost during cell transformation.

Identification and characterization of a novel isoform of human RNA polymerase III

This project concerns the identification of a novel isoform of human RNA polymerase III. It has been known for a while that Pol III transcribes small untranslated RNAs that intervene in essential cellular processes, such as transcription, splicing, regulation of mRNA-stability, translation and also protein translocation. Although being essential for homeostasis and cell survival, the importance of RNA polymerase III transcription for the regulation of cell growth and differentiation has not appropriately been appreciated for a long time. More recently, it has become clear that Pol III transcription activity is intimately linked to cellular transformation and that enhanced Pol III activity is a prerequisite for tumor cell growth. Despite this knowledge, little is known about the molecular mechanisms that may help to explain the co-regulation of Pol III transcription and tumoral growth.

We initially identified a novel protein that we designated as RPC32b because it exhibited high amino acid homology to the well known Pol III subunit RPC32 (hereafter referred to as RPC32a). The identification of RPC32b led to the demonstration of two human Pol III isoforms (Pol IIIa and Pol IIIb). RPC32b-containing Pol IIIb is ubiquitously expressed and essential for growth of human cells. Suppression of RPC32b by siRNAs is lethal in HeLa cells, suggesting that RPC32a-containing Pol IIIa cannot replace all functions of RPC32b-containing Pol IIIb. In contrast, Pol IIIa is dispensable for cell survival and its expression is restricted to undifferentiated human embryonic stem cells and to tumor cells. In this regard, and most importantly, suppression of RPC32a expression impedes anchorage-independent growth of HeLa cells whereas overexpression of RPC32a in a well defined cellular model system enhances colony formation in soft-agar assays. RP-C32a-induced cell transformation is accompanied by dramatic changes in the expression of several tumor-related mRNAs and proteins, including the repression of p53, increased expression of Aurora A, cyclin E or also the metastasis-associated protein S100 A4. Moreover, overexpression of RPC32a induces strongly enhanced expression of a subset of Pol III RNAs, including 7SK RNA, U6 RNA or 5S RNA, whilst the expression of other Pol III genes, notably of many tRNAs remains unchanged. These results suggest that RPC32a-containing Pol IIIa exerts important functions in the establishment and the maintenance of cells in an undifferentiated state. Taken together, our results identify a novel human Pol III isoform and isoform-specific functions in the regulation of cell growth and transformation (Haurie et al., 2010; Dumay-Odelot et al., 2010; Teichmann et al., 2010).

Regulation of RNA polymerase II transcription termination

In collaboration with the group of Pr Giorgio Dieci at the University of Parma, Italy, we analyzed the constraints in DNA sequences that are required for efficient transcription termination by human RNA polymerase III. We were able to show that many Pol III genes possess imperfect transcription termination sequences. These sequences allow transcription to proceed beyond the terminators, giving rise to RNA sequences that may be processed from the primary transcript and that may act as regulatory RNAs (Orioli et al., 2011a; Orioli et al., 2011b).

Structure-function studies of human RNA polymerase III subunit RPC62

In collaboration with the group of Sébastien Fribourg, we have been able to determine the structure of RPC62 by X-ray crystallography at a resolution of 2.85 Å. We analyzed the DNA-binding properties of RPC62 and of its protein interaction partner RPC39. We could show that RPC39 binds to double-stranded DNA, whereas RPC62 binds to single-stranded DNA. These data indicate that RPC39 and RPC62 may contribute to promoter melting and to the maintenance of the transcription bubble (Lefèvre et al., 2011).

Identification of mutations in the largest subunits of RNA polymerase III that may cause a recessive hypomyelinating Leukodystrophyof 

In collaboration with the laboratory of Dr. Bernard Brais (Departments of Pediatrics, Neurology and Neurosurgery, Montreal Children’s Hospital, McGill University Health Center, Montreal, Quebec, Canada), we identified and characterized mutations in the two largest subunits of human RNA polymerase III (POLR3A; POLR3B) that cause the onset of a recessive hypomyelinating leukodystrophy (tremor-ataxia with central hypomyelination [TACH]). TACH has been characterized as a childhood-onset hypomyelinating leukodystrophiy with prominent cerebellar dysfunction, oligodontia and hypogonadotropic hypogonadism. The protein levels of the POLR3A (RPC160) subunit were markedly reduced in affected individuals (Tétreault et al., 2011; Bernard et al., 2011).

Selected publications

• Tétreault M., Choquet K., Orcesi S., Tonduti D., Balottin U., Teichmann M., Fribourg S., Schiffmann R., Brais B., Vanderver A. and Bernard G. (2011). Recessive Mutations in POLR3B, Encoding the Second Largest Subunit of Pol III, Cause a Rare Hypomyelinating Leukodystrophy. Am. J. Hum. Genet. 89(5),652-655.

• Bernard G., Chouery E., Putorti M.L., Tétreault M., Takanohashi A., Carosso G., Clément I., Boespflug-Tanguy O., Rodriguez D., Delague V., Abou Ghoch J., Jalkh N., Dorboz I., Fribourg S., Teichmann M., Megarbane A., Schiffmann R., Vanderver A. and Brais B. (2011). Mutations of POLR3A Encoding a Catalytic Subunit of RNA Polymerase Pol III Cause a Recessive Hypomyelinating Leukodystrophy. Am. J. Hum. Genet. 89(3), 415-423.

• Orioli A., Pascali C., Pagano A., Teichmann M. and Dieci G. (2011). RNA polymerase III transcription control elements: themes and variations. Gene Jun 25. [Epub ahead of print].

• Orioli A., Pascali C., Quartararo J., Diebel K.W., Praz V., Romascano D., Percudani R., van Dyk L.F., Hernandez N., Teichmann M. and Dieci G. (2011). Widespread occurrence of non-canonical transcription termination by human RNA polymerase III. Nucleic Acids Res. 39, 5499-5512.

• Lefèvre S., Dumay-Odelot H., Budd A., Legran P., Pinaud N., Teichmann M. and Fribourg S. (2011). Structure - function analysis of hRPC62 provides insights into RNA polymerase III transcription initiation. Nature Structural & Molecular Biology, Mar;18(3):352-8.

• Teichmann M., Dieci G., Pascali C. and Boldina G (2010). General transcription factors and subunits of RNA polymerase III: Paralogues for promoter- and cell type-specific transcription in multicellular eukaryotes. Transcription, 1 (3), 130-135.

• Dumay-Odelot H., Durrieu-Gaillard S., Da Silva D., Roeder R.G., Teichmann M. (2010). Cell growth- and differentiation-dependent regulation of RNA polymerase III transcription. Cell Cycle.  9 (18), 3687-3699.
• Haurie V., Durrieu-Gaillard S., Dumay-Odelot H., Da Silva D., Rey C., Prochazkova M., Roeder R.G., Besser D. and Teichmann M. (2010). Two isoforms of human RNA polymerase III with specific functions in cell growth and transformation. Proc. Natl. Acad. Sci. USA., 107, 4176-4181.
• Dieci G., Fiorino G., Castelnuovo M., Teichmann M. and Pagano A. (2007) The expanding RNA polymerase III transcriptome. Trends Genet. 23 (12), 614-622.
• Dumay-Odelot H., Marck C., Durrieu-Gaillard S., Lefebvre O., Jourdain S., Prochazkova M., Pflieger A. and Teichmann M. (2007). Identification, molecular cloning, and characterization of the sixth subunit of human transcription factor TFIIIC. J. Biol. Chem. 282 (23): 17179-17189.

Research team

• Pr. Martin TEICHMANN Team leader
• Dr. Hélène DUMAY-ODELOT Assistant Professor (MC, Université Bordeaux Segalen)
• Dr. Chiara PASCALI Post-doc (INCa)
• Dr. Galina BOLDINA Post-doc (ANR)
• Stéphanie DURRIEU-GAILLARD Technician (Université Bordeaux Segalen)
• Daniel DA SILVA PhD Student (Université Bordeaux Segalen - MRT)
• Leyla EL AYOUBI PhD Student (Université Bordeaux Segalen)
• Khawla SEDDIKI Master Student (Université Bordeaux Segalen)

This team is part of the Unit “RNA: Natural and Artificial Regulation” (ARNA), INSERM/Université Bordeaux Segalen (Unit 869)