Molecular cloning and structure of an autosomal processed gene for human phosphoglycerate kinase

The human genome contains several DNA sequences homologous to cDNA for X-linked phosphoglycerate kinase (PGK). In the course of screening a genomic library containing a mutant gene for X-linked PGK (PGK-Matsue), we obtained a recombinant clone that cross-hybridizes to PGK cDNA. Restriction analysis suggests that the clone overlaps with a clone previously found to originate from chromosome 6, and which has been suggested to code for testis-specific PGK [Szabo et al., Proc. Natl. Acad. Sci. USA 81 (1984) 3167-3169]. The DNA fragment we have cloned contains 1252 bp that are homologous to the coding part of human PGK cDNA, and has an initiation codon, an in-phase termination codon, direct flanking repeats, and no introns. The maximum homology between the DNA and PGK cDNA is 85% at the coding nucleotide level, and it is 86.2% at the translated protein level; homology is also found in their 3'-flanking sequences and adenine-rich tails. These results suggest that the cloned DNA is most likely a processed pseudogene for PGK located on chromosome 6.