MTPAP is the only mitochondrial adenylase in flies and is required to protect the 3' termini of mRNAs.

<p>(<b>A</b>) Body size comparison in control (wt and FM7,Tb) and DmMTPAP KO larvae (<i>DmMTPAP</i>^KO) at 4 days ael. (<b>B</b>) qRT-PCR analysis of <i>DmMTPAP</i> transcript levels in 1 day heterozygous <i>DmMTPAP</i>^KO flies (<i>DmMTPAP</i>^KO/FM7,Tb) and 4-day-old hemyzygous <i>DmMTPAP</i>^KO larvae (<i>DmMTPAP</i>^KO) and their corresponding age-matched controls (wt, FM7,Tb). Histone 2B transcript was used as endogenous control. Data is represented as mean ± SEM (*P < 0.05, ***P < 0.001, n = 5). (<b>C</b>) mRNA and poly(A) tail length in individually sequenced clones after transcript circularisation (<i>MTATP6/8</i>, <i>MTND4/4L</i>, <i>MTND1</i> and <i>MTND5</i>) or 3' RACE (<i>MTCOX1</i> and <i>MTCYTB</i>) in <i>DmMTPAP</i>^KO (red, n = 14–26) and control larvae (grey, n = 11–25) at 4 days ael. The annotated 3' termini of the indicated transcripts was set to zero to determine poly(A) tail length. (<b>D</b>) rRNA and poly(A) tail length in individually sequenced clones after transcript circularisation in <i>DmMTPAP</i>^KO (red, n = 17–25) and control larvae (grey, n = 24–29) at 4 days ael. Data are represented as mean ± SEM. (***P < 0,001), using a Mann-Whitney test.