Transcriptomes of control and JAG1-deficient cochlea

The aim of this study is to identify the gene targets of the Notch ligand JAG1 in the postnatal cochlea. JAG1 was conditionally deleted in mice carrying both an inducible Cre allele (Sox2CreER) and a floxed (fl) Jag1 allele. Tamoxifen was administered to P0/P1 pups. Cochlear tissues from 6 Sox2CreER/+Jag1fl/fl and wildtype littermate controls were dissected under the dissecting microscope in ice-cold DEPC-treated PBS and stored in RNAlater (Invitrogen) at 4?C. The RNAs were purified by RNeasy Micro Kit (QIAGEN). The quality and quantity of RNAs were measured by a 2100 bioanalyzer (Agilent). Illumina compatible sequencing libraries were generated by the University of Rochester Genomics Research Center. Libraries were hybridized to the Illumina flow cell and single-end reads of 100nts were generated. Identification of significantly differentially expressed genes was determined using DeSeq2. We found 548 differentially expressed genes with an adjusted p-value of <0.05, 411 of those genes were significantly upregulated while 137 were significantly downregulated. Analysis of pathways revealed novel genes involved downstream of JAG1-Notch signaling in the postnatal cochlea. Overall design: To delete Jag1 in maturing cochlear supporting cells, we administered tamoxifen to Sox2CreER/+Jag1fl/fl (Jag1-mutant) and Sox2+/+ (control) mice at postnatal day (P)0/P1. At P6 we collected the cochlear sensory epithelium, extracted RNA and performed RNA-Seq. Six biological replicates of each genotype, Jag1-mutants and controls (wt), were compared.