SIGNIFICANT INCREASES IN THE STEADY-STATES OF PUTRESCINE AND SPERMIDINE SPERMINE N-1-ACETYLTRANSFERASE MESSENGER-RNA IN HELA-CELLS ACCOMPANIED BY GROWTH ARREST/

Polyamines are intrinsic polycations which play critical roles in cell proliferation. Ornithine decarbolylase (ODC) catalyzes the first step of polyamine biosynthesis converting ornithine to putrescine. In addi tion to polyamine degradation, spermidine/spermine acetyltransferase ( SSAT) regulates interconversion pathway of spermine and spermidine to putrescine. We quantified the polyamines and mRNAs of ODC and SSAT in HeLa S3 cells at various stages during exponential and plateau phases of culturing. Unexpectedly, putrescine and SSAT mRNA levels increased remarkably at the plateau phase, in contrast to the decrease of ODC mR NA level. It will be suggested that the putrescine has a novel functio n linked to the arrest of cell growth in which the SSAT-mediated pathw ay producing putrescine takes part. (C) 1998 Academic Press.