Sequence of the macronuclear DNA encoding large subunit ribosomal protein 29 (L29) in Euplotes crassus and XXXX sensitivity.

@entity1880 @entity19 @entity535 @entity14825 @entity375 @entity73363
As a first step towards developing a DNA transformation method for the ciliated protozoan Euplotes crassus we determined the minimum inhibitory concentration (MIC) for cell division in the presence of @entity1880 (Chx) for several cell lines and the range of Chx sensitivity for 106 different progeny cell lines derived by mating two lines. All of the cell lines are highly sensitive to Chx. Progeny cell lines show a wider range of sensitivities than the parental lines. Because site-directed mutagenesis of the RPL29 gene encoding the large subunit ribosomal protein 29 (L29) has been used to generate a Chx-resistance marker (ChxR) for another ciliate, @entity14825 [Yao and Yao, Proc. Natl. Acad. Sci. USA 88 (1991) 9493-9497], we isolated and sequenced the entire @entity73363 macronuclear DNA carrying RPL29. The encoded peptide is 52-73% identical in sequence to L29 sequences from organisms ranging from @entity14825 and @entity375 to @entity19 . In @entity73363 , the codon that has been mutated to confer Chx resistance in both @entity375 and @entity14825 already encodes the @entity535 residue of one of the mutant forms identified in these other organisms. Thus, @entity73363 RPL29 is not a convenient source of a selectable marker. Notable features of the macronuclear DNA carrying RPL29 are its extremely short non-coding regions and a TAG stop codon.
