Disruption of gene YlODC reveals absolute requirement of polyamines for mycelial development in Yarrowia lipolytica.
Polyamines are required for cellular growth and differentiation. In mammals and fungi they are synthesized via a pathway involving ornithine decarboxylase (ODC), which transforms ornithine into putrescine. We have cloned and disrupted the gene coding for ODC in Yarrowia lipolytica to analyze the role of polyamines in dimorphism of this fungus. Substrate- and cofactor-binding motifs, as well as two putative PEST boxes were identified in the amino acid sequence. A single transcript 1.7 kb in size was identified by Northern hybridization, and confirmed by rapid amplification of cDNA ends (RACE). Null mutants lacked ODC activity and behaved as polyamine auxotrophs. When low levels of polyamines were supplied to the null mutant, only yeast-like, but not mycelial growth was sustained. This phenomenon was confirmed by introduction of the YlODC gene under the control of an inducible promoter into the null mutant.
Jiménez-Bremont
J F
JF
Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Gto., Mexico.
Ruiz-Herrera
J
J
Dominguez
A
A
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D003470:Culture Media; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D008969:Molecular Sequence Data; D009955:Ornithine Decarboxylase / Q000235:genetics* / Q000378:metabolism; D011073:Polyamines / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D025062:Yarrowia / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development*
D003470:Culture Media; D005656:Fungal Proteins; D011073:Polyamines; D009955:Ornithine Decarboxylase