Subategory:

Mutants

Description:

This is a spontaneous methylammonium-resistant mutant isolated in the 4A+ background (MUT-4051). CR50 has a single base-pair change, from T to A on the sense strand, near the end of intron 4 of the AMT4 gene, encoding an ammonium transport protein. The change has apparently introduced a new splice site near the end of intron 4 by changing CUG to CAG in the transcript. It was reported that the sequence of the new spliced message obtained by RT-PCR shows the addition of CCC CUC CCC GCC CCG CCC CUC CAG to the major mRNA. Translation of this modified transcript results in the change of one amino acid and the addition of eight new residues in putative transmembrane segment 4. In addition to the major transcript there is a minor transcript (10-20% of the total) that is normal. CR50 retains residual Amt4 function.

Species:

Chlamydomonas

Locus:

AMT4

Chromosome:

13

Phenotype:

Inhibitor resistant (methylammonium)