Proteomic and Functional Characterization of a Chlamydomonas reinhardtii Mutant Lacking the Mitochondrial Alternative Oxidase 1

Abstract

In the present work, we have isolated by RNA interference and characterized at the functional and the proteomic levels a Chlamydomonas reinhardtii strain devoid of the mitochondrial alternative oxidase 1 (AOX1). The AOX1-deficient strain displays a remarkable doubling of the cell volume and biomass without alteration of the generation time or change in total respiratory rate, with a significantly higher ROS production. To identify the molecular adaptation underlying these observations, we have carried out a comparative study of both the mitochondrial and the cellular soluble proteomes. Our results indicate a strong up-regulation of the ROS scavenging systems and important quantitative modifications of proteins involved in the primary metabolism, namely an increase of enzymes involved in anabolic pathways and a concomitant general down-regulation of enzymes of the main catabolic pathways.

Inactivation of genes coding for mitochondrial Nd7 and Nd9 complex I subunits in Chlamydomonas reinhardtii. Impact of complex I loss on respiration and energetic metabolism

“…RNA interference also allowed us to gain insight into the role of other respiratory chain enzymes, such as F 1 F O ATP synthase (Lapaille et al, 2010), rotenone-insensitive alternative NAD(P)H dehydrogenase (Lecler et al, 2012) and cyanide-insensitive alternative oxidase (AOX) (Mathy et al, 2010).…”

“…To identify putative alterations of the energetic metabolism in complex I mutants (as previously observed for AOX-defective mutants of Chlamydomonas (Mathy et al, 2010)), a comparative study of the cellular soluble proteome has been undertaken on a mutant totally deprived of complex I (dum17 defective in mitochondrion-encoded ND6 subunit).…”

Respiratory-deficient mutants of the unicellular green alga Chlamydomonas: A review

“…1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 16 [17], (c) [68], (d) [69], (e) [70], (f) [71], (g) [72], (h) [73], (i) [74], (j) [75], (k) [76], (l) [77], (m) [22], (n) [29], (o) [78], (p) [58], (q) [79], (r)[34] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 17 ((a) [48], (b) [45], (c) [47], (d) [43], (e) [44], (f) [39], (g) …”

“…A mutant defective for the alternative oxidase (Aox1) has been isolated by RNA interference [58]. This AOX1-RNAi knock-down mutant displays a doubling of the cell volume and biomass without alteration of the generation time or change in total respiratory rate, with a significantly higher ROS production.…”

“…This AOX1-RNAi knock-down mutant displays a doubling of the cell volume and biomass without alteration of the generation time or change in total respiratory rate, with a significantly higher ROS production. A comparative study of both the mitochondrial and the cellular soluble proteomes was undertaken and indicated a strong up-regulation of the ROS scavenging systems and important modifications of proteins involved in the primary metabolism, namely an increase of enzymes involved in anabolic pathways and a concomitant general down-regulation of enzymes of the main catabolic pathways [58].…”