Human testis-specific PGK gene lacks introns and possesses characteristics of a processed gene

John R. McCarrey, Kelwyn Thomas

Research output: Contribution to journalArticlepeer-review

368 Scopus citations


Phosphoglycerate kinase (PGK) (ATP: 3-phospho-D-glycerate 1-phosphotransferase, EC is a metabolic enzyme functioning in the Embden-Meyerhof pathway that converts glucose (or fructose) to pyruvate. Two functional loci for the production of PGK have been identified in the mammalian genome. PGK-1 is an X-linked gene expressed constitutively in all somatic cells and premeitotic germ cells1-4.. The human PGK-1 gene consists of 11 exons and 10 introns encompassing a region ∼23 kilobases (kb) in length 5. PGK-2 is an autosomal gene expressed in a tissue-specific manner exclusively in the late stages of spermatogenesis3,4,6-8. In the present study, a molecular analysis of a human genomic clone of PGK-2 originally isolated by Szabo et al.9 has revealed that this autosomal sequence completely lacks introns and contains characteristics of a processed gene 10,11, or 'retroposon'12,13, including the remnants of a poly(A)+ tail and bounding direct repeats. Typically such processed sequences form non-functional pseudogenes that have evolved multiple genetic lesions which preclude translation of any transcript into a functional polypeptide10. For example, an X-linked processed pseudogene of PGK-1 (ψPGK-1) in humans has been identified and shown to contain premature termination codons in all reading frames14. It was therefore unexpected to find that the intronless autosomal PGK sequence reported here is not a pseudogene, but is rather a functional gene that has retained a complete open reading frame, and is actively expressed in mammalian spermatogenesis. Both the unusual conservation of function in this processed PGK-2 gene and its tissue-specific expression in spermatogenesis are best explained as a compensatory response to the inactivation of the X-linked PGK-1 gene in spermatogenic cells before meiosis.

Original languageEnglish (US)
Pages (from-to)501-505
Number of pages5
Issue number6112
StatePublished - 1987
Externally publishedYes

ASJC Scopus subject areas

  • General


Dive into the research topics of 'Human testis-specific PGK gene lacks introns and possesses characteristics of a processed gene'. Together they form a unique fingerprint.

Cite this