Differential expression of ATPAF1 and ATPAF2 genes encoding F1‐ATPase assembly proteins in mouse tissues

Abstract
Atp11p (Atpaf1p; F 1 -ATPase assembly factor 1) and Atp12p (Atpaf2p; F 1 -ATPase assembly factor 2) are proteins required for the assembly of β (F 1 -β) and α (F 1 -α) subunits into the mitochondrial ATPase. Here we report about 100 times lower levels of ATPAF1 and ATPAF2 transcripts in relation to the mRNA levels of F 1 -α and F 1 -β in a range of mouse tissues. Quantitative reverse-transcription polymerase chain reaction revealed nearly constant ATPAF1 expression in all tissues in both adult and 5-day-old mice (up to two-fold differences), indicating that ATPAF1 rather behaves like a maintenance gene. In contrast, ATPAF2 expression differed up to 30-fold in the tissues analysed. ATPAF2 tissue-specific expression was also found to correlate well with mRNA levels of both F 1 -α and F 1 -β (BAT≫kidney, liver>heart, brain>skeletal muscle), showing the highest mRNA level in the thermogenic, ATPase-poor brown adipose tissue, which is characterised by a 10-fold decrease in ATPase/respiratory chain stoichiometry relative to the other tissues.