Cjb. Hofmann et al., THE SMALLEST KNOWN EUKARYOTIC GENOMES ENCODE A PROTEIN GENE - TOWARDSAN UNDERSTANDING OF NUCLEOMORPH FUNCTIONS, MGG. Molecular & general genetics, 243(5), 1994, pp. 600-604
Cryptomonads are unicellular algae with plastids surrounded by four me
mbranes. Between the two pairs of membranes lies a periplastidal compa
rtment that harbours a DNA-containing organelle, termed the nucleomorp
h. The nucleomorph is the vestigial nucleus of a phototrophic, eukaryo
tic endosymbiont. Subcloning of parts of one nucleomorph chromosome re
vealed a gene coding for an Hsp70 protein. We demonstrate the expressi
on of this nucleomorph protein-coding gene and present a model for pro
tein transport from the host to the endosymbiont compartment.