title: GSM1629981: Gro-Seq plus Reelin; Mus musculus; OTHER
library_construction_protocol: Primary cortical neurons were incubated in swellinig ice-cold buffer (10mM Tris-Cl pH7.5, 2mM MgCl2, 3mM CaCl2) for 5min. Cells were lysed in lysis buffer (swelling buffer with 0.5% IGEPAL and 10% glycerol). The resultant nuclei were washed once again with 10 ml lysis buffer and then re-suspended in 100ml of freezing buffer (50mM Tris-Cl pH 8.3, 40% glycerol, 5mM MgCl2, 0.1mM EDTA). For run-on assay, resuspended nuclei were mixed with an equal volume of reaction buffer (10mM Tris-Cl pH 8.0, 5mM MgCl2, 1mM DTT, 300mM KCl, 20 units of SUPERase In, 1% sarkosyl, 500mM ATP, GTP, and Br-UTP, 2mM CTP) and incubated for 5 min at 30°C. The nuclear-run-on RNA (NRO-RNA) was then extracted with TRIzol LS reagent (Invitogen) following manufacturer’s instructions. NRO-RNA was then subjected to base hydrolysis on ice for 40 min and followed by treatment with DNase I and antarctic phosphatase. To purify the Br-UTP labeled nascent RNA, the NRO-RNA was immunoprecipitated with an anti-BrdU agarose beads (Santa Cruz Biotech) in binding buffer (0.5XSSPE, 1mM EDTA, 0.05% tween-20) for 1h at 4°C while rotating.  To repair the end, the immunoprecipitated BrU-RNA was re-suspended in 50mL reaction (43mL DEPC water, 5.2mL T4 PNK buffer, 1mL SUPERase In and 1mL T4 PNK (New England BioLabs)) and incubated at 37°C for 1h. RNA was then extracted, precipitated using acidic phenol-chloroform (Ambion) and subjected to poly-A tailing reaction by using poly-A polymerase (New England BioLabs) for 30 min at 37°C. Subsequently, reverse transcription was performed using oNTI223- primers (5’- pGATCGTCGGACTGTAGAACTCT; CAAGCAGAAGACGGCATACGATTTTTTTTTTTTTTTTTTTTVN-3’) where the p indicates 5’ phosphorylation, ‘;’ indicates the abasic dSpacer furan and VN indicates degenerate nucleotides. Specifically, tailed RNA (8.0mL) was subjected to reverse transcription using superscript III (Invitrogen), after which the cDNA products were separated on a 10% polyacrylamide TBE-urea gel. The extended first-strand product (100-500bp) was excised and recovered by gel extraction. After that, the first-strand cDNA was circularized by CircLigase (Epicentre) and re-linearized by Ape1 (New England BioLabs). Re-linearized single strand cDNA (sscDNA) was separated in a 10% polyacrylamide TBE gel as described above and the product of needed size was excised (~170-400bp) for gel extraction. Finally, sscDNA template was amplified by PCR using the Phusion High-Fidelity enzyme (NEB) according to the manufacturer’s instructions. Primers oNTI200 (5’-CAAGCAGAAGACGGCATA-3’) and oNTI201 (5’- AATGATACGGCGACCACCGACAGGTTCAGAGTTCTACAGTCCGACG-3’) were used to generate DNAs for deep sequencing.
attributes.tag: GEO Accession
attributes.value: GSM1629981