Isolation of a cDNA clone encoding S-adenosylmethionine decarboxylase. Expression of the gene in mitogen-activated lymphocytes.

摘要: S-Adenosylmethionine decarboxylase was purified from bovine liver and digested with endopeptidase Lys-C; the resulting peptides were chromatographically separated. Peptides containing either methionine or tryptophan subjected to sequence analysis. An oligonucleotide mixture of 48 sequences, which 17 nucleotides in length, synthesized based on one these peptide sequences. This synthetic labeled used screen a cDNA library phage lambda gt11. A clone identified contained 1350-nucleotide insert. insert nucleotide sequences coding for amino acid two that analyzed, thus proving this codes S-adenosylmethionine decarboxylase. subcloned fragment region as probe analyze expression gene mitogen-activated lymphocytes. Northern blots revealed message species 2.4 3.6 kilobases length. Both mRNAs coordinately expressed present polysomes. The levels increased approximately 4-fold by 9 h after activation cells. magnitude increase messages is be compared an 8- 10-fold rate synthesis protein. apparent translational efficiency upon lymphocyte confirmed analyzing polysomes In resting lymphocytes, average size mRNA 1.4 ribosomes per mRNA, value 2.7 stimulated Thus, it appears arises elevated initiation, leading more polysome encoding particular message. not general effect all proteins, since there no change cytoplasmic actin