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Figure 1

From: Circular mitochondrial-encoded mRNAs are a distinct subpopulation of mitochondrial mRNA in Trypanosoma brucei

Figure 1The alternative text for this image may have been generated using AI.

A subset of Trypanosoma brucei mitochondrial transcripts are circularized in the cell. (A) Schematic of primer placement and PCR products from linear and circularized RNA. CDS, coding sequence. (B) Schematic of the electron transport chain and mitochondrial ribosome with transcripts that were chosen for PCR analysis shown above the complexes of which they are a part (above). Complex II, shown in grey, does not have any subunits encoded in the mitochondrial genome. Length of bar is proportional to relative length of mRNA prior to editing (below). Green, regions that do not require editing prior to translation; maroon, regions that require editing prior to translation. ND1, NADH dehydrogenase subunit 1; CYb, cytochrome b; CO1, cytochrome c oxidase subunit 1; A6, ATP synthase subunit 6; RPS12, ribosomal protein S12. (C) Agarose gel of PCR products using circular oriented primers (top panels in A) for three different T. brucei mitochondrial transcripts from cDNA made from RNA of ‘control’ cells as defined in “Materials and methods”. The smear of DNA is from the variation in tails lengths and is expected for these products. L1, T4 RNA ligase (Epicentre) added; L2, T4 RNA ligase (New England BioLabs) added; NL, no ligase added. Pre, pre-edited; e, edited. (D) Agarose gels of PCR products from RNA treated with ligase (+L) and without ligase (−L) of insect stage (top) and mammalian bloodstream stage (bottom) T. brucei for five mitochondrial transcripts. Transcripts that are edited have different primer sets to amplify their pre-edited (p) or edited (e) sequences. The blank well for +L CYbe in the bottom gel is expected because edited CYb transcripts are not found in bloodstream stage parasites. Transcripts that produced products from −L RNA are bolded. Brackets indicate expected sizes of PCR products. A6, CYb, and RPS12 were run on one gel for insect stage and one gel for bloodstream stage. CO1 and ND1 were run on the same gel for insect and bloodstream stage. Arrows indicate excess primers. Gel images are cropped. Original gels are presented in Fig. S5.

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