E-MTAB-7161
RNA-Seq of A375 cells treated with tetracycline-based crosslinking probes, with and without competition by parent tetracyclines, to show specific binding of the tetracycline analogs Col-3 and doxycycline on rRNA substructures of the human ribosome
Upon finding that the tetracyclines COL-3 and doxycycline target unique rRNA substructures of the 80S ribosome (E-MTAB-7147), we confirmed these putative ribosomal binding sites by showing that tetracycline-based crosslinking probes are specifically competed from these rRNA structures by their parent drugs. In short, we incorporated dual bioorthogonal handles into tetracycline-based probes, containing both a photoactive diazirine to enable direct probe crosslinking to the human ribosome and an azide handle to allow selective enrichment of crosslinked biomolecules via copper-free 'click' chemistry. The COL-3 and doxycycline probes were each incubated with A375 cells, followed by irradiation at 365 nm to induce photolysis of the diazirine moiety and subsequent crosslinking to adjacent ribosomal components. Pulldown and RNA-Seq of the crosslinked RNAs from our experiments were used to identify enrichment of reverse transcription (RT) stops at ribosomal RNA sites caused by local crosslinking of our probes. In these experiments, UV crosslinking was preformed with the COL-3 and doxycycline probe compounds in the presence and absence of free COL-3 and doxycycline (i.e., parent tetracycline molecules lacking the bifunctional diazirine-azide moiety), which were used as competitors to specifically diminish crosslinking to the ribosomal RNA. Crosslinking to ribosomal RNA was determined using RNA-Seq based RT stop enrichment, which was was also compared to inactive tetracycline probes containing a modified bifunctional linker, a non-specific aniline probe, and untreated controls.
Upon finding that the tetracyclines COL-3 and doxycycline target unique rRNA substructures of the 80S ribosome (E-MTAB-7147), we confirmed these putative ribosomal binding sites by showing that tetracycline-based crosslinking probes are specifically competed from these rRNA structures by their parent drugs. In short, we incorporated dual bioorthogonal handles into tetracycline-based probes, containing both a photoactive diazirine to enable direct probe crosslinking to the human ribosome and an azide handle to allow selective enrichment of crosslinked biomolecules via copper-free 'click' chemistry. The COL-3 and doxycycline probes were each incubated with A375 cells, followed by irradiation at 365 nm to induce photolysis of the diazirine moiety and subsequent crosslinking to adjacent ribosomal components. Pulldown and RNA-Seq of the crosslinked RNAs from our experiments were used to identify enrichment of reverse transcription (RT) stops at ribosomal RNA sites caused by local crosslinking of our probes. In these experiments, UV crosslinking was preformed with the COL-3 and doxycycline probe compounds in the presence and absence of free COL-3 and doxycycline (i.e., parent tetracycline molecules lacking the bifunctional diazirine-azide moiety), which were used as competitors to specifically diminish crosslinking to the ribosomal RNA. Crosslinking to ribosomal RNA was determined using RNA-Seq based RT stop enrichment, which was was also compared to inactive tetracycline probes containing a modified bifunctional linker, a non-specific aniline probe, and untreated controls.