CC-146 nr1-1 spr-u-1-6-2 mt-

Locus: 16S rRNA, chloroplast genome
Locus: NR1, linkage group VIII

Source: From a cross by Gillham of spr-u-1-6-2 mt+ x nr-u-2-1 sr-u-2-60 mt-, selected as a potential recombinant resistant to both spectinomycin and nearmine, but sensitive to streptomycin.

Comment: When outcrossed to wild type, the neamine resistance in this strain showed Mendelian segregation, and the strain was not cross-resistant to kanamycin, nor were chloroplast ribosomes resistant to neamine in poly-U directed amino acid incorporation. Therefore this strain contains a new spontaneous neamine-resistance mutation. Subsequently this was mapped to linkage group VIII and shown to be allelic with other nuclear nr1 mutants. This particular allele was designated nr1-1, and is the allele present in a number of derivative strains, including CC-975, CC-1088, CC-1144, CC-1714, CC-1720, CC-1730, CC-1735, and probably CC-2645.

This is a good strain to use either for spr-u-1-6-2 or nr1 in mt-.