Our team

Georges Beaud, Researcher

Laurent Chavatte, group leader, CNRS

Ghania Hammad, Master2 student

Hélène Jean-Jacques, technician, CNRS

Yona Legrain, PhD student

Zahia Touat, postdoctoral fellow

Our address

CNRS - Centre de Génétique Moléculaire

Avenue de la Terrasse - Bât. 26

91198 GIF-SUR-YVETTE Cedex

FRANCE

Phone : 33 (0)1 69 82 31 49

Telecopy : 33 (0)1 69 82 31 50

Research themes

Our group has been created within the Centre de Génétique Moléculaire in October 2007 with a young investigator grant (ATIP CNRS).

My long term goal is to understand the mechanisms of selenoprotein synthesis and regulation in mammalian cells. Selenium is an essential trace element which is incorporated into a small but crucial family of proteins, the selenoproteins as selenocysteine, the 21st amino acid. Among the twenty five selenoporteins in human, some have fundamental roles in dealing with oxidative stress and therefore would protect the body against cancer risks, cardiovascular diseases, and viral and bacterial infections.

Selenoproteins synthesis follows a remarkable mechanism which involves translational recoding of a UGA codon, normally used as a stop signal, into a selenocysteine codon. In eukaryotes, a specific secondary structure in the 3’ UTR of the selenoprotein mRNA, named SECIS, is required to direct faithful recoding. Several components of the eukaryotic Sec insertion machinery have been characterized so far: a Sec-tRNA^Sec, an elongation factor EFsec, and two SECIS binding protein (SBP2 and ribosomal protein L30). In our model, SBP2 and L30 have distinct functions in UGA/Sec recoding mechanism with the SECIS element working as a molecular switch upon protein binding.

Our goals are (i) to understand the mechanism of translational recoding of UGA as selenocysteine by delineating structure, function and assembly of the selenocysteine insertion machinery and (ii) to investigate the regulation of selenoprotein synthesis in mammalians cells.

Mots Clés : selenium / selenocysteine / translational regulation / macromolecular complexes / oxidative stress / UGA codon.

Selected publications

Latrèche, L., Jean-Jean, O., Driscoll, D. and Chavatte, L. (2009) Novel structural determinants in human SECIS elements modulate the translational recoding of UGA as selenocysteine. Nucleic Acids Res, 12 (5) 408-16.

Chavatte, L., Brown, B. and Driscoll, D. (2005) Ribosomal protein L30 is a component of UGA-Sec recoding machinery in eukaryotes. Nature Struct and Mol Biol 12, 408-16.

Bulygin, K., Chavatte, L., Frolova,L., Karpova, G. and Favre, A. (2005) The first position of a codon placed in the A site of the human 80S ribosome contacts nucleotide C1696 of the 18S rRNA as well as proteins S2, S3, S3a, S30 and S15. Biochemistry 44, 2153-2162

Sampath, P., Mazumder, B., Seshadri, V., Gerber, C., Chavatte, L., Kinter, M., Dignam, D., Kim, S., Driscoll, D. and Fox, P. (2004) Non-canonical translational silencing activity of Glutamyl-prolyl-tRNA synthetase. Cell 119, 105-208.

Driscoll, D. and Chavatte, L. (2004) Finding needles in a haystack: in silico identification of eukaryotic selenoprotein genes. EMBO Reports 3, 140-141.

Chavatte, L., Laugâa, P., Frolova, L., Kisselev, L. and Favre, A. (2003) Stop codons and UGG promote efficient binding of the polypeptide release factor eRF1 to the ribosomal A site. J. Mol. Biol. 331, 745-758.

Chavatte, L., Kervestin, S., Favre, A. and Jean-Jean, O. (2003) Stop codon selection in eukaryotic translation termination: comparison of the discriminating potential between human and ciliate eRF1s. EMBO J. 22, 1644-1653.

Chavatte, L., Seit-Nebi, A., Dubovaya, V. and Favre, A. (2002) The invariant uridine of stop codons contacts the NIKSR loop of eRF1 in the ribosome. EMBO J. 21, 5302-5311.

Chavatte, L., Frolova, L., Kisselev, L. and Favre, A. (2001) The polypeptide chain release factor eRF1 specifically contacts the s⁴UGA stop codon located in the A site of eukaryotic ribosomes, Eur. J. Biochem. 268, 2896-2904.