TY  - JOUR
A1  - Jäger, Dominik
A1  - Pernitzsch, Sandy R.
A1  - Richter, Andreas S.
A1  - Backofen, Rolf
A1  - Sharma, Cynthia M.
A1  - Schmitz, Ruth A.
T1  - An archaeal sRNA targeting cis- and trans-encoded mRNAs via two distinct domains
JF  - Nucleic Acids Research
N2  - We report on the characterization and target analysis of the small (s) RNA\(_{162}\) in the methanoarchaeon Methanosarcina mazei. Using a combination of genetic approaches, transcriptome analysis and computational predictions, the bicistronic MM2441-MM2440 mRNA encoding the transcription factor MM2441 and a protein of unknown function was identified as a potential target of this sRNA, which due to processing accumulates as three stabile 5' fragments in late exponential growth. Mobility shift assays using various mutants verified that the non-structured single-stranded linker region of sRNA\(_{162}\) (SLR) base-pairs with the MM2440-MM2441 mRNA internally, thereby masking the predicted ribosome binding site of MM2441. This most likely leads to translational repression of the second cistron resulting in dis-coordinated operon expression. Analysis of mutant RNAs in vivo confirmed that the SLR of sRNA\(_{162}\) is crucial for target interactions. Furthermore, our results indicate that sRNA\(_{162}\)-controlled MM2441 is involved in regulating the metabolic switch between the carbon sources methanol and methylamine. Moreover, biochemical studies demonstrated that the 50 end of sRNA\(_{162}\) targets the 5'-untranslated region of the cis-encoded MM2442 mRNA. Overall, this first study of archaeal sRNA/mRNA-target interactions unraveled that sRNA\(_{162}\) acts as an antisense (as) RNA on cis- and trans-encoded mRNAs via two distinct domains, indicating that cis-encoded asRNAs can have larger target regulons than previously anticipated.
KW  - strain
KW  - escherichia coli
KW  - methanosarcina mazei GO1
KW  - methanol methyltransferase isozymes
KW  - small nucleolar RNAs
KW  - acetivorans C2A
KW  - antisense RNAs
KW  - GO1
KW  - transcriptional regulator
KW  - translational initiation
KW  - pyrococcus furiosus
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-134972
VL  - 40
IS  - 21
ER  - 
TY  - JOUR
A1  - McCarthy, J. E.
A1  - Schairer, H. U.
A1  - Sebald, Walter
T1  - Translational initiation frequency of atp genes from Escherichia coli: identification of an intercistronic sequence that enhances translation
N2  - The c, b and ö subunit genes of the Escherichia coli atp operon were cloned individually in an expression vector between the tac fusion promoter and the galK gene. The relative rates of subunit synthesis directed by the cloned genes were similar in vitro andin vivo and compared favourably with the subunit stoichiometry of the assembled proton-translocating A TP synthase of E. coli in vivo. The rate of synthesis of subunit c was at least six times that of subunit b and 18 times that of subunit ö. Progressive shortening of the long intercistronic sequence lying upstream of the subunit c gene showed that maximal expression of this gene is dependent upon the presence of a sequence stretching > 20 bp upstream of the Shine-Dalgarno site. This sequence thus acts to enhance the rate of translational initiation. The possibility that similar sequences might perform the same function in other operons of E. coli and bacteriophage A is also discussed. Translation of the subunit b cistron is partially coupled to translation of the preceding subunit c cistron. In conclusion, the expression of all the atp operon genes could be adjusted to accommodate the subunit requirements of A TP synthase assembly primarily by means of mechanisms which control the efficiency of translational initiation and re-initiation at the respective cistron start codons.
KW  - Biochemie
KW  - E. coli atp operon
KW  - subunit stoichiometry
KW  - in vitro and in vivo expression
KW  - translational initiation
Y1  - 1985
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62657
ER  -