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Stage specific expression of poly(malic acid)‐affiliated genes in the life cycle of Physarum polycephalum
Author(s) -
Pinchai Nadthanan,
Lee BongSeop,
Holler Eggehard
Publication year - 2006
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2006.05131.x
Subject(s) - physarum polycephalum , complementary dna , biology , gene knockdown , malic acid , plasmodium (life cycle) , suppression subtractive hybridization , gene expression , microbiology and biotechnology , rna , gene , biochemistry , cdna library , parasite hosting , citric acid , world wide web , computer science
Polymalic acid is receiving interest as a unique biopolymer of the plasmodia of mycetozoa and recently as a biogenic matrix for the synthesis of devices for drug delivery. The acellular slime mold Physarum polycephalum is characterized by two distinctive growth phases: uninucleated amoebae and multinucleated plasmodia. In adverse conditions, plasmodia reversibly transform into spherules. Only plasmodia synthesize poly(malic acid) (PMLA) and PMLA‐hydrolase (polymalatase). We have performed suppression subtractive hybridization (SSH) of cDNA from amoebae and plasmodia to identify plasmodium‐specific genes involved in PMLA metabolism. We found cDNA encoding a plasmodium‐specific, spherulin 3a‐like polypeptide, NKA48 (spherulin 3b), but no evidence for a PMLA‐synthetase encoding transcript. Inhibitory RNA (RNAi)‐induced knockdown of NKA48 ‐cDNA generated a severe reduction in the level of PMLA suggesting that spherulin 3b functioned in regulating the level of PMLA. Unexpectedly, cDNA of polymalatase was not SSH‐selected, suggesting its presence also in amoebae. Quantitative PCR then revealed low levels of mRNA in amoebae, high levels in plasmodia, and also low levels in spherules, in agreement with the expression under transcriptional regulation in these cells.