Cloning and direct sequencing of plant promoters using primer-adapter mediated PCR on DNA coupled to a magnetic solid phase

Biotechniques. 1992 Jul;13(1):74-81.

Abstract

A method that allows amplification and direct sequencing or cloning of an unknown DNA segment flanked by a known sequence is described using barley genomic DNA. The method avoids the step of circularization necessary for inverse PCR by ligation of primer-adapters to restricted genomic DNA. Specificity is achieved in the first amplification step; linear PCR with a biotinylated primer complementary to the known flanking sequence (primer 1-B) produces a single-stranded product that is purified employing streptavidin-coated magnetic beads. After this step, which removes genomic DNA, two rounds of exponential PCR are performed, first with the adapter-primer and primer 1 and second with primer 1 substituted by a nested primer 2. If the second primer is biotinylated, the product can be sequenced directly using solid-phase sequencing. We have employed this method to sequence directly and to clone the promoters of two late embryogenesis-abundant (Lea) genes (B19.4 and B19.3) from barley. Lea B19.4 and B19.3 encode putative desiccation-protective proteins that act in the final stages of embryogenesis and have previously been cloned as cDNAs. We demonstrate here that their proximal promoter regions are very similar (80% identity) and that both contain putative abscisic acid-responsive elements.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Blotting, Southern
  • Cloning, Molecular / methods*
  • DNA / genetics
  • Hordeum / genetics
  • Magnetics
  • Molecular Sequence Data
  • Multigene Family
  • Polymerase Chain Reaction / methods*
  • Promoter Regions, Genetic*
  • Templates, Genetic

Substances

  • DNA

Associated data

  • GENBANK/X65951
  • GENBANK/X65952