Pinchai, Nadthanan and Lee, Bong-Seop and Holler, Eggehard
Stage specific expression of poly(malic acid)-affiliated
genes in the life cycle of Physarum polycephalum. Spherulin 3b and polymalatase. FEBS Journal 273 (5), pp. 1046-1055.
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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.
|Institutions:||Biology, Preclinical Medicine > Institut für Biophysik und physikalische Biochemie|
|Keywords:||Physarum polycephalum; plasmodium; polymalatase, polymalic acid; spherulin 3b|
|Subjects:||500 Science > 570 Life sciences|
|Refereed:||Yes, this version has been refereed|
|Created at the University of Regensburg:||Yes|
|Deposited On:||14 Jul 2006|
|Last Modified:||20 Jul 2011 20:48|