Programmed translational frameshifting is likely required for expressions of genes encoding putative nuclear protein kinases of the ciliate Euplotes octocarinatus

Three macronuclear genes encoding putative nuclear protein kinases of the c iliate Euplotes octocarinatus syngen 1 were isolated and sequenced. All thr ee deduced gene products share significant properties with a group of recen tly identified nuclear serine/threonine protein kinases named Ndr, The thre e predicted proteins contain the twelve conserved catalytic subdomains of p rotein kinases and 22 near universally-conserved amino acids residues that are characteristic of serine/threonine protein kinases. In addition, there is an similar to 30 amino acid-peptide insertion between subdomains VII and VIII that contains a potential nuclear localization signal. Sequence analy sis suggests that expression of the Eondr2 gene requires a +1 programmed tr anslational frameshift for its translation. Comparison of the deduced EoNdr 2 with other known Ndr protein kinases implies that a +1 ribosomal frameshi ft occurs at the motif AAATAA.