Transcriptional regulation of acetyl CoA and lipid synthesis by P_II protein in Synechococcus PCC 7942

Abstract

P protein family is widespread in prokaryotes and plants. In this study, impacts of P deficiency on the synthesis of acetyl CoA and acetyl CoA carboxylase enzyme (ACCase) was analyzed in the Synechococcus sp. PCC 7942 by evaluating the mRNA levels of pyruvate kinase (PK), pyruvate dehydrogenase (PDH), citrate synthase (CS), biotin synthase (BS), biotin carboxylase (BC), biotin carboxyl carrier protein (BCCP), carboxyl transferase (CT) α and β subunits. The P deficient Synechococcus sp. PCC 7942 showed upregulation of all the above-mentioned genes, except CS. Analyses of genes required for acetyl coA synthesis exhibited a substantial increase in the transcript levels of PK and PDH in the P mutant strain. In addition, the P mutant also displayed reduced acetyl CoA content, high ACCase activity, and increased lipid content. The lessening of acetyl CoA content was attributed to the rapid utilization of acetyl CoA in fatty acid synthesis as well as in the TCA cycle whereas the increased ACCase activity was ascribed to the rise in mRNA levels of BS, BC, BCCP, CT α, and β genes. However, increased lipid content was correlated with the declined total protein content. Hence, the study suggested that P protein regulates the synthesis of acetyl CoA and ACCase enzyme at the transcriptional level.

Engineering the fatty acid synthesis pathway in Synechococcus elongatus PCC 7942 improves omega-3 fatty acid production

“…The information related to FA synthesis regulation in Se7942 focuses on the signal transduction protein P II . The P II mutant strain of Se7942 showed a decreased intracellular acetyl-CoA content and enhanced activity of the acetyl-CoA–carboxylase complex through transcriptional activation of the accABCD genes [60]. However, P II does not regulate the enzymes involved in the FAS system.…”

Photosynthetic Conversion of Carbon Dioxide to Oleochemicals by Cyanobacteria: Recent Advances and Future Perspectives

“…Additionally, the global regulator LexA was found to repress the expression of some fab genes (Kizawa et al, 2017), while a transcriptional regulator, CyAbrB2, was found to inhibit the FFA production in Syn6803 (Kawahara et al, 2016). The global nitrogen regulator PII protein was shown to negatively regulate cyanobacterial fatty acid biosynthesis by transcriptional control (Verma et al, 2018) or by interacting with biotin carboxyl carrier protein (BCCP) which is a subunit of ACCase (Hauf et al, 2016).…”