Insect ornithine decarboxylase (ODC) complements SPE1 knock-out of yeast Saccharomyces cerevisiae.
Ornithine decarboxylase (ODC) is a rate-limiting enzyme in the biosynthesis of polyamines, which are essential for cell growth, differentiation, and proliferation. This report presents the characterization of an ODC-encoding cDNA (SlitODC) isolated from a moth species, the tobacco cutworm, Spodoptera litura (Lepidoptera); its expression in a polyamine-deficient strain of yeast, S. cerevisiae; and the recovery in polyamine levels and proliferation rate with the introduction of the insect enzyme. SlitODC encodes 448 amino acid residues, 4 amino acids longer than B. Mori ODC that has 71% identity, and has a longer C-terminus, consistent with B. mori ODC, than the reported dipteran enzymes. The null mutant yeast strain in the ODC gene, SPE1, showed remarkably depleted polyamine levels; in putrescine, spermidine, and spermine, the levels were > 7, > 1, and > 4%, respectively, of the levels in the wild-type strain. This consequently caused a significant arrest in cell proliferation of > 4% of the wild-type strain in polyaminefree media. The transformed strain, with the substituted SlitODC for the deleted endogenous ODC, grew and proliferated rapidly at even a higher rate than the wild-type strain. Furthermore, its polyamine content was significantly higher than even that in the wild-type strain as well as the spe1-null mutant, particularly with a very continuously enhanced putrescine level, reflecting no inhibition mechanism operating in the putrescine synthesis step by any corresponding insect ODC antizymes to SlitODC in this yeast system.
Choi
Soon-Yong
SY
Department of Biotechnology, Hannam University, Daejeon 306-791, Korea.
Park
Hee Yun
HY
Paek
Aron
A
Kim
Gil Seob
GS
Jeong
Seong Eun
SE
D000123:Acetyltransferases; D000818:Animals; D015317:Biogenic Polyamines / Q000378:metabolism; D012831:Bombyx / Q000201:enzymology / Q000235:genetics; D048708:Cell Growth Processes / Q000235:genetics; D055786:Gene Knockout Techniques; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009955:Ornithine Decarboxylase / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D018411:Spodoptera / Q000201:enzymology* / Q000235:genetics; D014170:Transformation, Genetic
D015317:Biogenic Polyamines; D019476:Insect Proteins; D029701:Saccharomyces cerevisiae Proteins; D000123:Acetyltransferases; C107119:SUR4 protein, S cerevisiae; D009955:Ornithine Decarboxylase