TRANSGENIC MICE OVER-EXPRESSING THE HUMAN SPERMIDINE SYNTHASE GENE

We have generated a transgenic mouse line harbouring the functional (c hromosome-1-derived) human spermidine synthase (EC2.5.1.16) gene in th eir genome. The transgenic animals expressed the human gene-derived mR NA, as revealed by reverse-transcriptase/PCR analysis, in all tissues studied and displayed tissue spermidine synthase activity that was 2-6 times that in their syngenic littermates. The elevated spermidine syn thase activity, however, had virtually no effect on tissue putrescine, spermidine or spermine levels. The view that the accumulation of sper midine and spermine is possibly controlled by S-adenosylmethionine dec arboxylase was further supported by the finding that tissue spermidine and spermine contents also remained practically normal in hybrid tran sgenic mice over-expressing both human ornithine decarboxylase and spe rmidine synthase genes.