Translation of CircRNAs.
Circular RNAs (circRNAs) are abundant and evolutionarily conserved RNAs of largely unknown function. Here, we show that a subset of circRNAs is translated in vivo. By performing ribosome footprinting from fly heads, we demonstrate that a group of circRNAs is associated with translating ribosomes. Many of these ribo-circRNAs use the start codon of the hosting mRNA, are bound by membrane-associated ribosomes, and have evolutionarily conserved termination codons. In addition, we found that a circRNA generated from the muscleblind locus encodes a protein, which we detected in fly head extracts by mass spectrometry. Next, by performing in vivo and in vitro translation assays, we show that UTRs of ribo-circRNAs (cUTRs) allow cap-independent translation. Moreover, we found that starvation and FOXO likely regulate the translation of a circMbl isoform. Altogether, our study provides strong evidence for translation of circRNAs, revealing the existence of an unexplored layer of gene activity.
Biological Chemistry Department, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Nagarjuna Reddy
NR
Pamudurti
Biological Chemistry Department, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Osnat
O
Bartok
Systems Biology of Gene Regulatory Elements, Max-Delbrück-Center for Molecular Medicine, Berlin 13125, Germany.
Marvin
M
Jens
Biological Chemistry Department, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Reut
R
Ashwal-Fluss
Systems Biology of Gene Regulatory Elements, Max-Delbrück-Center for Molecular Medicine, Berlin 13125, Germany.
Christin
C
Stottmeister
Non Coding RNAs and Mechanisms of Cytoplasmic Gene Regulation, Max-Delbrück-Center for Molecular Medicine, Berlin 13125, Germany.
Larissa
L
Ruhe
Biological Chemistry Department, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Mor
M
Hanan
RNA Biology and Posttranscriptional Regulation, Max-Delbrück-Center for Molecular Medicine, Berlin 13125, Germany.
Emanuel
E
Wyler
Mass Spectrometry Core Unit, Max-Delbrück-Center for Molecular Medicine, Berlin 13125, Germany.
Daniel
D
Perez-Hernandez
Mass Spectrometry Core Unit, Max-Delbrück-Center for Molecular Medicine, Berlin 13125, Germany.
Evelyn
E
Ramberger
Biological Chemistry Department, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Shlomo
S
Shenzis
Biological Chemistry Department, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Moshe
M
Samson
Mass Spectrometry Core Unit, Max-Delbrück-Center for Molecular Medicine, Berlin 13125, Germany.
Gunnar
G
Dittmar
RNA Biology and Posttranscriptional Regulation, Max-Delbrück-Center for Molecular Medicine, Berlin 13125, Germany.
Markus
M
Landthaler
Non Coding RNAs and Mechanisms of Cytoplasmic Gene Regulation, Max-Delbrück-Center for Molecular Medicine, Berlin 13125, Germany.
Marina
M
Chekulaeva
Systems Biology of Gene Regulatory Elements, Max-Delbrück-Center for Molecular Medicine, Berlin 13125, Germany.
Nikolaus
N
Rajewsky
Biological Chemistry Department, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel. Electronic address: skadener@mail.huji.ac.il.
Sebastian
S
Kadener
D000818:Animals; D002460:Cell Line; D018387:Codon, Initiator; D018388:Codon, Terminator; D029721:Drosophila Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D051858:Forkhead Transcription Factors / Q000378:metabolism; D005838:Genotype; D006257:Head; D013058:Mass Spectrometry; D051379:Mice; D009154:Mutation; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000235:genetics; D009690:Nucleic Acid Conformation; D009752:Nutritional Status; D010641:Phenotype; D014176:Protein Biosynthesis; D012313:RNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012315:RNA Caps / Q000737:chemistry / Q000235:genetics; D000079962:RNA, Circular; D051381:Rats; D012270:Ribosomes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013217:Starvation / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D014162:Transfection
D018387:Codon, Initiator; D018388:Codon, Terminator; D029721:Drosophila Proteins; C477334:FOXO protein, Drosophila; D051858:Forkhead Transcription Factors; D009687:Nuclear Proteins; D012315:RNA Caps; D000079962:RNA, Circular; C109271:mbl protein, Drosophila; D012313:RNA
cap-independent; circRNA; muscleblind; translation