to 10 base pairs) and corresponds to the anticodon stem of trnas, yet without an anticodon loop (as not required for tmrna function). p2 stabilizes the trna-like structure, but four nucleotides invariant across oomycetes and jakobids suggest an additional, currently unidentified function. p3 has five base pairs and corresponds to the t-arm of trnas, yet with different consensus nucleotides both in the paired region and the loop. the t-loop sequence is conserved across oomycetes and jakobid, with only few deviations (e.g., saprolegnia ferax). finally, instead of the trna-like d-stem with a shortened three-nucleotide d-loop characteristic for bacterial tmrnas, mitochondrial counterparts have a highly variable 5 to 14-nt long loop. the intervening sequence (int.) of two-piece mt-tmrnas is a+u rich and of irregular length (4-34 nt). ). for secondary structure models of one- and two-piece mt-tmrnas see figure 1. mt-tmrna processing and expression processing of two-piece mt-tmrna. the four major rna processing sites are numbered (1-4). processing at sites 1 and 4 is thought to occur by a tmrna-specific activity, site 2 by rnase p and site 3 by a 3’ trna endonuclease processing. nucleotides cleaved from the precursor are in gray; the post-transcriptionally added cca is boxed. rna-seq data of phytophthora sojae show an expression level similar to that of neighboring mitochondrial trnas, and four major processing sites confirm the predicted termini of mature mt-tmrna. the tmrna precursor molecule is likely processed by rnase p and a trna 3’ processing endonuclease (see figure 2); the latter activity is assumed to lead to the removal of the intervening sequence. following the addition of cca at the 3’ discriminator nucleotide, the tmrna can be charged by alanyl-trna synthetase with alanine.