Mamm Genome 1999 Aug;10(8):784-8
The functional intronless S-adenosylmethionine decarboxylase gene
of the mouse (Amd-2) is linked to
the ornithine decarboxylase gene (Odc) on chromosome 12 and is
present
in distantly related species of
the genus Mus.
Persson K, Heby O, Berger FG.
Department of Cellular and Developmental Biology, Umea University, S-901 87 Umea, Sweden.
S-Adenosylmethionine decarboxylase (AdoMetDC) is a key enzyme in the biosynthesis of polyamines. We have previously identified a mouse AdoMetDC gene that exhibits the hallmarks of a retroposon; that is, it has no introns, is flanked by direct repeats, and has a poly(dA) tract at its 3'-end. This gene, termed Amd-2, is not a processed pseudogene; rather, it is transcribed in a variety of mouse tissues and encodes a functional enzyme. In the current report, we present the sequence of a 6.7-kb genomic segment of the Amd-2 locus. Several sequences of interest, including an intercisternal A particle (IAP) element, a transposon-related sequence, and several expressed sequence tags (ESTs), were found within or near Amd-2. We also show, through analysis of an interspecific backcross, that Amd-2 is located on Chr 12, tightly linked to the gene (Odc) that encodes ornithine decarboxylase, another key enzyme in polyamine synthesis. Finally, we show that Amd-2 is present among several divergent species of the genus Mus. Thus, the integration event that generated Amd-2 may have occurred early during Mus evolution.