G1-To-S-Phase Transition 1 (GSPT1)

GST1, seemed to be essential for the G1- to S-phase transition in the yeast cell cycle. The gene product appeared to be a GTP-binding protein of molecular mass 76,565 Da with 38% identity in amino acid sequence with the alpha subunit of elongation factor-1.

The deduced 635-amino acid protein has a unique N terminus and a conserved C-terminal eukaryotic elongation factor-1-alpha-like domain. The mouse and human Gspt1 proteins share 94% sequence identity. RT-PCR analysis indicated expression of Gspt1 in all mouse tissues examined.GSPT1 bound the p19(ARF) isoform of CDKN2A, but not the p16(INK4A) isoform.