title: Differential stability of mitochondrial mRNA in HeLa cells.
abstract: The physiological significance and metabolism of oligoadenylated and polyadenylated human mitochondrial mRNAs are not known to date. After study of eight mitochondrial transcripts (ND1, ND2, ND3, ND5, CO1, CO2, ATP6/8 and Cyt. b) we found a direct correlation between the half-lives of mitochondrial mRNAs and their steady-state levels. Investigation of the mt-mRNA decay after thiamphenicol treatment indicated that three transcripts (ND2, ND3 and Cyt. b) are significantly stabilized after inhibition of mitochondrial translation. Careful analysis one of them, ND3, showed that inaccurate processing of the H-strand RNA precursor may occasionally occur between the ND3 and tRNA(Arg) locus leading to synthesis of ND3 mRNAs lacking the STOP codon. However, analysis of the oligo(A) fraction observed in case of the ND3 indicates that partially polyadenylated mRNAs are linked rather to the transcription process than to the translation-dependent deadenylation. Analysis of ND3 mRNA turnover in cells with siRNA-mediated knock-down of the mitochondrial poly(A) polymerase shows that strongly decreased polyadenylation does not markedly affect the decay of this transcript. We present a model where oligoadenylated mitochondrial transcripts are precursors of molecules containing full length poly(A) tails.
authors.affiliation: Department of Genetics, Warsaw University and Warszawa, Poland.
authors.forename: Janusz
authors.initials: J
authors.lastname: Piechota
authors.forename: Rafał
authors.initials: R
authors.lastname: Tomecki
authors.forename: Kamil
authors.initials: K
authors.lastname: Gewartowski
authors.forename: Roman
authors.initials: R
authors.lastname: Szczesny
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Dmochowska
authors.forename: Marek
authors.initials: M
authors.lastname: Kudła
authors.forename: Lien
authors.initials: L
authors.lastname: Dybczyńska
authors.forename: Piotr P
authors.initials: PP
authors.lastname: Stepien
authors.forename: Ewa
authors.initials: E
authors.lastname: Bartnik
mesh_terms: D015152:Blotting, Northern; D018388:Codon, Terminator; D006367:HeLa Cells; D006801:Humans; D008928:Mitochondria / Q000378:metabolism; D009691:Nucleic Acid Denaturation; D011062:Polynucleotide Adenylyltransferase / Q000737:chemistry; D014176:Protein Biosynthesis; D012313:RNA / Q000737:chemistry*; D034622:RNA Interference; D012333:RNA, Messenger / Q000737:chemistry*; D000077278:RNA, Mitochondrial; D034741:RNA, Small Interfering / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013839:Thiamphenicol / Q000494:pharmacology; D014158:Transcription, Genetic
chemical_list: D018388:Codon, Terminator; D012333:RNA, Messenger; D000077278:RNA, Mitochondrial; D034741:RNA, Small Interfering; D012313:RNA; D011062:Polynucleotide Adenylyltransferase; D013839:Thiamphenicol