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Fluorescence Based Primer Extension Technique to Determine Transcriptional Starting Points and Cleavage Sites of RNases In Vivo
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The mRNA interferases, MazF-mt3 and MazF-mt7 from Mycobacterium tuberculosis target unique pentad sequences in

Ling Zhu1, Sangita Phadtare, Hirofumi Nariya

  • 1Department of Biochemistry, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.

Molecular Microbiology
|May 20, 2008
PubMed

Insights

Mycobacterium tuberculosis MazF-mt3 and MazF-mt7 mRNA interferases cleave specific RNA sequences. This differential mRNA degradation may regulate protein expression and aid bacterial adaptation during infection.

Area of Science:

  • Molecular Biology
  • Bacteriology
  • Genetics

Background:

  • Toxin-antitoxin (TA) systems encode mRNA interferases, which are sequence-specific endoribonucleases.
  • Mycobacterium tuberculosis possesses at least seven MazF homologues.
  • Previous studies determined cleavage specificities for MazF-mt1 and MazF-mt6.

Purpose of the Study:

  • To develop a general method for determining longer recognition sequences for mRNA interferases.
  • To determine the specific RNA cleavage sites for M. tuberculosis MazF-mt3 and MazF-mt7.
  • To identify M. tuberculosis mRNAs potentially resistant to MazF-mt3 and MazF-mt7 cleavage.

Main Methods:

  • A novel method using phage MS2 RNA and CspA, an RNA chaperone, was employed.
  • The method allows determination of recognition sequences longer than three bases.
  • Bioinformatics analysis identified underrepresented pentad sequences in M. tuberculosis genes.

Main Results:

  • MazF-mt3 cleaves RNA at UU CCU or CU CCU sequences.
  • MazF-mt7 cleaves RNA at U CGCU sequences.
  • Pentad sequence recognition by MazF-mt3 and MazF-mt7 is highly specific and underrepresented in PE and PPE gene families.

Conclusions:

  • MazF-mt3 and MazF-mt7 exhibit specific, longer RNA sequence recognition.
  • Differential mRNA degradation by these interferases may regulate protein expression.
  • This regulatory mechanism could facilitate M. tuberculosis adaptation to host environments.

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