GSM8721642: 3Months_mouseBORG_BMS753; Mus musculus; OTHER
Organoids are fixed with 4% paraformaldehyde, 6% sucrose for 20 min, washed 3 x 5 min with PBS and suspended in 30% sucrose at 4°C overnight. Several organoids are placed in plastic molds and submerged in OCT compound and frozen before being cryo-sectioned using a cryo-star. Frozen brain organoid molds are cryosectioned and deposited on top of in-house manufactured DNA arrays as described previously (Lozachmeur et al. Cell reports Methods 2023). Briefly, in-house manufactured DNA arrays are composed by a double-barcoded part encoding their unique position within the array, and a poly-T extremity allowing to capture messanger RNA. Deposited tissue sections were processed for library preparation as described in our in-house protocol (Lozachmeur et al; Cell Reports Methods 2023). At the end of the process, libraries were used for Illumina sequencing (150 nts paired-ends sequencing; NovaSeq; >200 million reads per library).