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Addition of poly(A) and heteropolymeric 3' ends in Bacillus subtilis wild-type and polynucleotide

Juan Campos-Guillén1, Patricia Bralley, George H Jones

  • 1Departamento de Ingeniería Genética de Plantas, CINVESTAV, U. Irapuato, México.

Journal of Bacteriology
|July 5, 2005
PubMed

Insights

In Bacillus subtilis, RNA 3' end modifications, including polyadenylation, occur independently of polynucleotide phosphorylase (PNPase). This suggests alternative mechanisms for RNA processing and decay in this bacterium.

Area of Science:

  • Molecular Biology
  • Bacterial Genetics
  • RNA Metabolism

Background:

  • Polyadenylation is crucial for bacterial mRNA decay and stable RNA quality control.
  • In Escherichia coli, poly(A) polymerase I (PAP I) is the primary polyadenylating enzyme, but polynucleotide phosphorylase (PNPase) also adds 3' tails.
  • Bacillus subtilis lacks a clear PAP I homologue, necessitating investigation into its RNA 3' end modification mechanisms.

Purpose of the Study:

  • To investigate the nature of 3'-tail addition in Bacillus subtilis.
  • To determine the role of PNPase in RNA 3' end modification in B. subtilis.
  • To characterize the types and patterns of nucleotide additions to RNA 3' ends in B. subtilis.

Main Methods:

  • RNA isolation from wild-type and pnpA mutant Bacillus subtilis strains.
  • Sizing of poly(A) sequences on RNA 3' ends.
  • cDNA cloning and sequencing of RNA 3'-end sequences.
  • Analysis of polyadenylated and heteropolymeric end modifications.

Main Results:

  • RNA 3' end modifications, including polyadenylation and heteropolymeric additions, were observed in both wild-type and PNPase-deficient B. subtilis strains.
  • Modified ends were predominantly found on incomplete transcripts, suggesting roles in RNA decay.
  • Heteropolymeric ends, averaging 40 nucleotides, showed complex but similar sequences across multiple clones.

Conclusions:

  • PNPase is not the major enzyme responsible for adding nucleotides to RNA 3' ends in Bacillus subtilis.
  • Alternative enzymatic pathways likely mediate RNA 3' end modification and processing in B. subtilis.
  • The findings highlight species-specific differences in bacterial RNA metabolism.

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