title: The abundant and essential HU proteins in Deinococcus deserti and Deinococcus radiodurans are translated from leaderless mRNA.
abstract: HU proteins have an important architectural role in nucleoid organization in bacteria. Compared with HU of many bacteria, HU proteins from Deinococcus species possess an N-terminal lysine-rich extension similar to the eukaryotic histone H1 C-terminal domain involved in DNA compaction. The single HU gene in Deinococcus radiodurans, encoding DrHU, is required for nucleoid compaction and cell viability. Deinococcus deserti contains three expressed HU genes, encoding DdHU1, DdHU2 and DdHU3. Here, we show that either DdHU1 or DdHU2 is essential in D. deserti. DdHU1 and DdHU2, but not DdHU3, can substitute for DrHU in D. radiodurans, indicating that DdHU3 may have a non-essential function different from DdHU1, DdHU2 and DrHU. Interestingly, the highly abundant DrHU and DdHU1 proteins, and also the less expressed DdHU2, are translated in Deinococcus from leaderless mRNAs, which lack a 5'-untranslated region and, hence, the Shine-Dalgarno sequence. Unexpectedly, cloning the DrHU or DdHU1 gene under control of a strong promoter in an expression plasmid, which results in leadered transcripts, strongly reduced the DrHU and DdHU1 protein level in D. radiodurans compared with that obtained from the natural leaderless gene. We also show that the start codon position for DrHU and DdHU1 should be reannotated, resulting in proteins that are 15 and 4 aa residues shorter than initially reported. The expression level and start codon correction were crucial for functional characterization of HU in Deinococcus.
authors.affiliation: 1​Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, Bâtiment 409, F-91405 Orsay, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Bouthier de la Tour
authors.affiliation: 2​CEA, DSV, IBEB, Lab Bioenerget Cellulaire, F-13108 Saint-Paul-lez-Durance, France 3​CNRS, UMR 7265 Biol Veget & Microbiol Environ, F-13108 Saint-Paul-lez-Durance, France 4​Aix-Marseille Université, F-13108 Saint-Paul-lez-Durance, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Blanchard
authors.affiliation: 1​Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, Bâtiment 409, F-91405 Orsay, France 3​CNRS, UMR 7265 Biol Veget & Microbiol Environ, F-13108 Saint-Paul-lez-Durance, France 4​Aix-Marseille Université, F-13108 Saint-Paul-lez-Durance, France 5​CEA, DSV, IBEB, Lab Ecol Microb Rhizosphere & Environ Extrem, F-13108 Saint-Paul-lez-Durance, France.
authors.forename: Rémi
authors.initials: R
authors.lastname: Dulermo
authors.affiliation: 2​CEA, DSV, IBEB, Lab Bioenerget Cellulaire, F-13108 Saint-Paul-lez-Durance, France 3​CNRS, UMR 7265 Biol Veget & Microbiol Environ, F-13108 Saint-Paul-lez-Durance, France 4​Aix-Marseille Université, F-13108 Saint-Paul-lez-Durance, France.
authors.forename: Monika
authors.initials: M
authors.lastname: Ludanyi
authors.affiliation: 1​Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, Bâtiment 409, F-91405 Orsay, France.
authors.forename: Alice
authors.initials: A
authors.lastname: Devigne
authors.affiliation: 6​CEA-Marcoule, DSV/IBITEC-S/SPI/Li2D, Laboratory 'Innovative technologies for Detection and Diagnostic', BP 17171, F-30207 Bagnols-sur-Cèze, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Armengaud
authors.affiliation: 1​Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, Bâtiment 409, F-91405 Orsay, France.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Sommer
authors.affiliation: 3​CNRS, UMR 7265 Biol Veget & Microbiol Environ, F-13108 Saint-Paul-lez-Durance, France 2​CEA, DSV, IBEB, Lab Bioenerget Cellulaire, F-13108 Saint-Paul-lez-Durance, France 4​Aix-Marseille Université, F-13108 Saint-Paul-lez-Durance, France.
authors.forename: Arjan
authors.initials: A
authors.lastname: de Groot
mesh_terms: D020121:5' Untranslated Regions; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018387:Codon, Initiator / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D034301:Deinococcus / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D020121:5' Untranslated Regions; D001426:Bacterial Proteins; D018387:Codon, Initiator; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; C040330:histone-like protein HU, bacteria