Molecular Cloning and Characterization of the Mouse Geranylgeranyltransferase fi Subunit Gene

The mouse Geranylgeranyl transferase βcatalytic subunit gene has been recently isolated from a mouse E8.5 cDNA library. We now report the full length cDNA and the genomic structure of this gene. Compared to the cDNA from rat brain, the mouse GGTase β subunit has 8 extra amino acid immediately following the ATG start codon. This gene spans a distance of more than 16 kbs and is organised into 8 exons. All the exon/intron junction sequences follow the GT/AG rule. The transcriptional initiation start site is located at 166 base pair upstream of the translation initiation codon. The 419 bp of the 5' flanking region sequence contains potential binding sites for several transcription factors (AP-1, NF-kB, CAAT box, NF-IL6), but no typical TATA box. Northern blot analysis of the expression of this gene shows that cyctoheximide(CHX) markedly induces steady-state accumulation of the GGTase β mRNA. The increase in steady-state expression can be detected as early as 2 hr and the maximum level of expression occurs at 4-6 hr. Actinomycin D treatment after superinduction with CHX results in slower degradation rate of the GGTase βgene, indicating that CHX increases the stability of the GGTase β mRNA.