Pseudoprimers cause somatic hypermutation of Ig genes

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Analysis of Somatic Hypermutation in the JH4 intron of Germinal Center B cells from Mouse Peyer's Patches
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Analysis of Somatic Hypermutation in the JH4 intron of Germinal Center B cells from Mouse Peyer's Patches

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A M Olovnikov1

  • 1Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 125319, Russia. am@olovnikov.msk.ru.

Biochemistry. Biokhimiia
|January 23, 1999
PubMed

Insights

Hypermutation in immunoglobulin (Ig) genes may occur due to "misprimers" (MPs) that compete with true primers during DNA replication. These MPs, formed from cleaved transcripts, possess an incorrect base, inducing errors in DNA synthesis.

Area of Science:

  • Immunology
  • Molecular Biology
  • Genetics

Background:

  • Immunoglobulin (Ig) gene hypermutation is a critical process for adaptive immunity.
  • The precise molecular mechanisms driving Ig gene hypermutation remain under investigation.

Purpose of the Study:

  • To propose a novel mechanism for Ig gene hypermutation involving "misprimers" (MPs).
  • To elucidate the role of MPs in inducing errors during DNA replication.

Main Methods:

  • The study proposes a theoretical model based on molecular interactions.
  • Analysis of nascent transcript processing and DNA polymerase activity.

Main Results:

  • "Misprimers" (MPs), derived from cleaved nascent transcripts, possess an erroneous 3' terminus.
  • MPs compete with true primers for DNA binding.
  • Wobbling of the unpaired 3' end of MPs leads to DNA polymerase errors.

Conclusions:

  • The "misprimer" (MP) mechanism offers a plausible explanation for Ig gene hypermutation.
  • This mechanism highlights the role of transcript processing errors in generating genetic diversity.

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