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Autophagy has emerged as a key regulator of cell metabolism. Recently, we have demonstrated that autophagy is involved in RNA metabolism by regulating ribosomal RNA (rRNA) synthesis. We found that autophagy-deficient cells display much higher 47S precursor rRNA level, which is caused by the accumulation of SQSTM1/p62 (sequestosome 1) but not other autophagy receptors. Mechanistically, SQSTM1 accumulation potentiates the activation of MTOR (mechanistic target of rapamycin kinase) complex 1 (MTORC1) signaling, which facilitates the assembly of RNA polymerase I pre-initiation complex at ribosomal DNA (rDNA) promoter regions and leads to the activation of rDNA transcription. Finally, we showed that SQSTM1 accumulation is responsible for the increase in protein synthesis, cell growth and cell proliferation in autophagy-deficient cells. Taken together, our findings reveal a regulatory role of autophagy and autophagy receptor SQSTM1 in rRNA synthesis and may provide novel mechanisms for the hyperactivated rDNA transcription in autophagy-related human diseases. Abbreviations: 5-FUrd: 5-fluorouridine; LAP: MAP1LC3/LC3-associated phagocytosis; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; PIC: pre-initiation complex; POLR1: RNA polymerase I; POLR1A: RNA polymerase I subunit A; rDNA: ribosomal DNA; RRN3: RRN3 homolog, RNA polymerase I transcription factor; rRNA: ribosomal RNA; SQSTM1/p62: sequestosome 1; TP53INP2: tumor protein p53 inducible nuclear protein 2; UBTF: upstream binding transcription factor. [ABSTRACT FROM AUTHOR]

The sequenced mitochondrial genome of the threatened alpine butterflyParnassius nomionincludes 13 protein-coding genes (ND1-6, COI-III, ATP6, ATP8, ND4, ND4L, CTYB), 2 ribosomalRNAs (12 Sand16 S), 22 transferRNAs, which is 14,547 bp in length. Its gene order and orientation are identical to the common type found in most of other completely sequenced lepidopteran mitogenomes. All protein-coding genes are initiated by ATN codons, except forCOI, which uses CGA as its start codon. Eleven PCGs use the standard TAA as their termination codon, andCOI, COIIuse the incomplete termination codon T. [ABSTRACT FROM AUTHOR]

The sequenced mitochondrial genome of the cabbage webwormHellula undalisincludes 13 protein-coding genes (PCGs) (nad1-6, cox1-3, atp6, atp8, nad4Landcob), two ribosomalRNAs (12Sand16S) and 19 transferRNAs, which is 14,678 bp in length. Its gene order and orientation are identical to the common types found in most of the other completely sequenced lepidopteran mitogenomes. Thirteen PCGs start with a typical ATN codon, whilecox1uses CGA as its start codon. Some PCGs use the standard TAA as their termination codon, while others use the incomplete termination codon T (cox1, cox2andnad4). [ABSTRACT FROM AUTHOR]