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The smallest known eukaryotic genomes encode a protein gene: towards an understanding of nucleomorph functions


Cryptomonads are unicellular algae with plastids surrounded by four membranes. Between the two pairs of membranes lies a periplastidal compartment that harbours a DNA-containing organelle, termed the nucleomorph. The nucleomorph is the vestigial nucleus of a phototrophic, eukaryotic endosymbiont. Subcloning of parts of one nucleomorph chromosome revealed a gene coding for an Hsp70 protein. We demonstrate the expression of this nucleomorph protein-coding gene and present a model for protein transport from the host to the endosymbiont compartment.

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Correspondence to U. -G. Maier.

Additional information

This paper is dedicated to Prof. Dr. Peter Sitte on the occasion of his 65th birthday

Communicated by H. Saedler

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Hofmann, C.J.B., Rensing, S.A., Häuber, M.M. et al. The smallest known eukaryotic genomes encode a protein gene: towards an understanding of nucleomorph functions. Molec. Gen. Genet. 243, 600–604 (1994).

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Key words

  • Cryptomonads
  • Periplastidal
  • Hsp70
  • Transport