Stable Transformation of Chlorella: Rescue of Nitrate Reductase-Deficient Mutants with the Nitrate Reductase Gene

Journal Article

Unicellular green algae, like Chlorella, offer a potentially useful system for the expression of heterologous proteins. However, the development of Chlorella as a bioreactor has been delayed owing to the lack of a stable transformation technique. Here we report on the use of micro-projectile bombardment to introduce the nitrate reductase (NR) gene from Chlorella vulgaris into NR-deficient Chlorella sorokiniana mutants, resulting in stable transformants. The stable transformants were able to grow on nitrate medium after repeated passages between selective and nonselective medium and exhibited inducible nitrate reductase activity comparable to that of wild-type cells. Southern analysis suggests homologous recombination occurs with insertion of the wild type gene into the mutated gene and that the genes of the two Chlorellaspecies used are very similar. Specific RNase protection assays, selecting for a poorly conserved region of the gene, identified the presence of the C. vulgaris NR transcript only in the transformed C. sorkiniana mutant and not in the mutant.

Full Text

Duke Authors

Cited Authors

  • Dawson, HN; Burlingame, R; Cannons, AC

Published Date

  • December 1997

Published In

Volume / Issue

  • 35 / 6

Start / End Page

  • 356 - 362

PubMed ID

  • 9353220

Electronic International Standard Serial Number (EISSN)

  • 1432-0991


  • eng

Conference Location

  • United States