mRNA sequencing analysis of transcripts from hippocampus of Wt1∆ mice

Purpose: Study the differentially expressed genes in the hippocampus of mice, comparing Wt1∆ mice with their control wild type littermates in basal conditions (naïve untrained animals). Methods: Forebrain-specific deletion of Wt1 was achieved by crossing animals homozygous for the conditional Wt1 knockout allele (Wt1fl/fl) with a transgenic line, Camk2a-Cre, (B6.Cg-Tg(Camk2a-cre)T29-1Stl/J; Jackson Lab: http://jaxmice.jax.org/strain/005359.html). Expression of Cre recombinase resulted in the in-frame deletion of exons 8 and 9 and generated a truncated allele encoding a shortened non functional WT1 protein lacking zinc fingers 2 and 3 in their forebrain (starting at P21). Brains of Wt1∆ mice (n=2) and their control littermates (wild type; n=2) were removed, dorsal hippocampi were dissected and used for library preparation. The seq library was prepared using TruSeq RNA Sample Prep Kit v2 protocol (Illumina, CA, USA). For the RNA-Seq data analysis Tophat 2.0.13, bowtie 2.1.0 , samtool 0.1.7 and cufflinks 1.3.0 were used. The rn5-bowtie2 index was generated with the command 'bowtie2-build rn5.fa rn5'. The 'rn5.fa'-file was downloaded from the UCSC genome browser. The mm10-bowtie2 index was downloaded from http://bowtie-bio.sourceforge.net/bowtie2/manual.shtml. RefSeq geneTracks and GTF-files for the rn5 and mm10 genome assembly were downloaded from UCSC genome browser. Common gene ids in the GTF-files were matched to individual transcript_ids using the corresponding official symbols obtained from the geneTracks files. Conclusions: Our study illustrates the nature of the different transcripts in Wt1∆ mice compared to their control wild type littermates at basal state (untrained). This experiment allowed us to identify wich genes are modulated in the hippocampus by the transcription fator WT1. mRNA profiles from dorsal hippocami Wt1∆ mice and control wild type littermates were generated by deep sequencing using TruSeq RNA Sample Prep Kit v2 protocol (Illumina, CA, USA).