ABSTRACT: Purpose: Investigation of effects of early adversity in mice deficient for brain serotonin on the transcriptome Methods: Following materal separation in early childhood and behavioural screening in adulthood, 4 moth old males, either wildtype or carrying a hetero- or homozygous knockout of the thryptophan hyroxylase 2 gene, were sacrificed, brains extracted, the amygdalae of both hemispheres dissected, blended and separated in two protions. From one of these portions RNA was extracted. Extracted RNA was further processed by an external company, i.e. IGA Technologies (Udine, Italy). , library preparation was performed using TruSeq Stranded Total RNA Library Prep Kit (Illumina, San Diego, CA, US) that captures coding RNA and multiple forms of non-coding RNA, with a total input of 300 ng of RNA, as measured with Qubit 2.0 Fluorometer (Invitrogen, Carlsbad, CA) following manufacturer’s recommendations. The sequencing was performed using the Illumina HiSeq 2500 platform at a read-length of 125 bp with paired end reads yielding 60 million reads/sample. Reads were mapped to the Mus musculus GRCm38.p5 genome using STAR (Dobin et al. 2013). Following mapping, the reads per position were determined using HTSeq (Anders et al. 2015). Results: Either Tph2 genotype, early adversity as well as their interaction resulted in unique profiles of differentially expressed RNA. As expected, the effect sizes and significances were rather subtle. Conclusion: Tph2, MS and their interaction induced changes in gene expression and DNA methylation, within a physiological range. The observed changes by MS seemed furthermore strongly influenced by the Tph2 genotype, ergo brain 5-HT availability.
