The RAG2 gene of the yeast Kluyveromyces lactis codes for a putative phosphoglucose isomerase.

In a s t r a i n of K. l a c t i s . the RAG 2 gene (1) i s found as a recessive a l l e l i c form, rap2. The s t ra in cannot grow on glucose if the respi ra tory pathway i s blocked by mitochondrial i n h i b i t o r s . The RAG2 gene has been cloned and i t s nucleot ide sequence determined. The 557 aminoacids long open reading frame has a homology of 56,5% with mouse neuroleukine (2) which has recently been shown to be ident ical to the phosphoglucose isomerase (3 ,4) . The phenotype of the rag2 s t ra in may be explained by a defect of th i s enzyme in the g lyco ly t ic pathway.