Genomic organization of the glyceraldehyde-3-phosphate dehydrogenase gene family of Caenorhabditis elegans

Xin Yun Huang, Lilli Ann M. Barrios, Panpim Vonkhorporn, Sandra Honda, Donna G. Albertson, Ralph M. Hecht

Research output: Contribution to journalArticlepeer-review


Glyceraldehyde-3-phosphate dehydrogenase (GAPDHase) is encoded by four genes designated gpd-1 through gpd-4 in the nematode Caenorhabditis elegans. gpd-1 has been isolated and sequenced, and is shown here to have a nearly identical copy (gpd-4) with respect to coding and regulatory flanking sequence information as well as to the placement of its two introns. Both genes, which are separated by 250,000 to 300,000 base-pairs were assigned to chromosome II by in situ hybridization and physically linked to a DNA polymorphism located near unc-4 on the genetic map. The genes gpd-2 and gpd-3 are also nearly identical with each other but differ from the gpd-1 and gpd-4 pair with respect to the positions of their two introns and a cluster of amino acid changes within the amino-terminal region of the enzyme. Furthermore, one gene from each pair (gpd-4 and gpd-2) exhibits a single amino acid substitution at positions heretofore known to be conserved in all other systems so far examined including the extreme thermophiles. gpd-2 and gpd-3 are organized as a direct tandem repeat separated by only 244 base-pairs. They have been assigned to an 85,200 base-pair contig that maps to the left end of the X chromosome. The absence of gpd-3 from C. elegans var. Bergerac was used as a marker to map the gpd-2,3 gene pair near unc-20. Northern analyses have shown that gpd-1 and gpd-4 are preferentially expressed in embryos, while the expression of gpd-2 and gpd-3 increases during postembryonic development. These analyses indicate that the gpd-1,4 gene pair encodes the minor isoenzyme, GAPDHase-1, present in all cells of the nematode while the other gene pair (gpd-2,3) encodes the major isoenzyme, GAPDHase-2, preferentially expressed in the body-wall muscle. The G + T-rich and T-rich regions essential for vertebrate β-globin polyadenylation were also observed for gpd-3.

Original languageEnglish (US)
Pages (from-to)411-424
Number of pages14
JournalJournal of Molecular Biology
Issue number3
StatePublished - Apr 5 1989

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology


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