Insertional Mutagenesis by a Hybrid PiggyBac and Sleeping Beauty Transposon in the Rat
GENETICS
Authors: Furushima, Kenryo; Jang, Chuan-Wei; Chen, Diane W.; Xiao, Ningna; Overbeek, Paul A.; Behringer, Richard R.
Abstract
A hybrid piggyBac/Sleeping Beauty transposon-based insertional mutagenesis system that can be mobilized by simple breeding was established in the rat. These transposons were engineered to include gene trap sequences and a tyrosinase (Tyr) pigmentation reporter to rescue the albinism of the genetic background used in the mutagenesis strategy. Single-copy transposon insertions were transposed into the rat genome by co-injection of plasmids carrying the transposon and RNA encoding piggyBac transposase into zygotes. The levels of transgenic Tyr expression were influenced by chromosomal context, leading to transgenic rats with different pigmentation that enabled visual genotyping. Transgenic rats designed to ubiquitously express either piggyBac or Sleeping Beauty transposase were generated by standard zygote injection also on an albino background. Bigenic rats carrying single-copy transposons at known loci and transposase transgenes exhibited coat color mosaicism, indicating somatic transposition. PiggyBac or Sleeping Beauty transposase bigenic rats bred with wild-type albino rats yielded offspring with pigmentation distinct from the initial transposon insertions as a consequence of germline transposition to new loci. The germline transposition frequency for Sleeping Beauty and piggyBac was similar to 10% or about one new insertion per litter. Approximately 50% of the insertions occurred in introns. Chimeric transcripts containing endogenous and gene trap sequences were identified in Gabrb1 mutant rats. This mutagenesis system based on simple crosses and visual genotyping can be used to generate a collection of single-gene mutations in the rat.
Neurotransmitter and Neuromodulator Genes Associated With a History of Depressive Symptoms in Individuals With Alcohol Dependence
ALCOHOLISM-CLINICAL AND EXPERIMENTAL RESEARCH
Authors: Kertes, Darlene A.; Kalsi, Gursharan; Prescott, Carol A.; Kuo, Po-Hsiu; Patterson, Diana G.; Walsh, Dermot; Kendler, Kenneth S.; Riley, Brien P.
Abstract
Background: Depressive symptoms are common among individuals with alcohol use disorders and impact treatment outcome. Substantial overlap exists among the neurobiological systems proposed in the pathophysiology of depressive and alcohol use disorders; however, specific genetic effects contributing to risk for depressive comorbidity remain poorly understood. Methods: This study examines the association of depressive symptom scores for lifetime depression (the sum of DSM-IV major depression co-endorsed criteria for lifetime depression) with markers in 120 candidate genes in 554 alcohol-dependent individuals. The candidate genes code for molecules involved in dopamine, serotonin, glutamate, gamma-aminobutyric acid (GABA), and opioid neurotransmission, cell signaling, pharmacokinetics, stress biology, and behavioral control. Analyses were conducted at the single marker level with experimentwise permutation to control for multiple testing. Results: Results revealed nominal associations for markers in 20 genes. Following experimentwise permutation, markers in the corticotropin-releasing hormone-binding protein (CRHBP) the mu-opioid receptor (OPRM1) and the beta 1 subunit of GABA A (GABA(A)) receptors (GABRB1) met or exceeded the significance threshold. None of the markers associated with depressive symptom scores were significantly associated with alcohol dependence symptom scores. Conclusion: These findings suggest potential risk genes for depressive symptoms in alcohol-dependent individuals.