Disrupting a gene to determine its effect on an organism's phenotype is an indispensable tool in molecular biology. Such techniques are critical for understanding how a gene product contributes to the development and cellular identity of organisms. The explosion of genomic sequencing technologies combined with recent advances in genome‐editing techniques has elevated the possibilities of genetic manipulations in numerous organisms in which these experiments were previously not readily accessible or possible. Introducing the next generation of molecular biologists to these emerging techniques is key in the modern biology classroom. This comprehensive review introduces undergraduates to CRISPR/Cas9 editing and its uses in genetic studies. The goals of this review are to explain how CRISPR functions as a prokaryotic immune system, describe how researchers generate mutations with CRISPR/Cas9, highlight how Cas9 has been adapted for new functions, and discuss ethical considerations of genome editing. Additionally, anticipatory guides and questions for discussion are posed throughout the review to encourage active exploration of these topics in the classroom. Finally, the supplement includes a study guide and practical suggestions to incorporate CRISPR/Cas9 experiments into lab courses at the undergraduate level. © 2018 The Authors Biochemistry and Molecular Biology Education published by Wiley Periodicals, Inc. on behalf of International Union of Biochemistry and Molecular Biology, 46(2):195–205, 2018.

As the only catalytic member of the Sir-protein gene-silencing complex, Sir2's catalytic activity is necessary for silencing. The only known role for Sir2's catalytic activity in Saccharomyces cerevisiae silencing is to deacetylate N-terminal tails of histones H3 and H4, creating high-affinity binding sites for the Sir-protein complex, resulting in association of Sir proteins across the silenced domain. This histone deacetylation model makes the simple prediction that preemptively removing Sir2's H3 and H4 acetyl substrates, by mutating these lysines to unacetylatable arginines, or removing the acetyl transferase responsible for their acetylation, should restore silencing in the Sir2 catalytic mutant. However, this was not the case. We conducted a genetic screen to explore what aspect of Sir2's catalytic activity has not been accounted for in silencing. Mutation of a nonsirtuin histone deacetylase, Rpd3, restored Sir-protein-based silencing in the absence of Sir2's catalytic activity. Moreover, this antagonism could be mediated by either the large or the small Rpd3-containing complex. Interestingly, this restoration of silencing appeared independent of any known histone H3 or H4 substrates of Rpd3 Investigation of Sir-protein association in the Rpd3 mutant revealed that the restoration of silencing was correlated with an increased association of Sir proteins at the silencers, suggesting that Rpd3 was an antagonist of Sir2's function in nucleation of Sir proteins to the silencer. Additionally, restoration of silencing by Rpd3 was dependent on another sirtuin family member, Hst3, indicating multiple antagonistic roles for deacetylases in S. cerevisiae silencing.

To fully appreciate genetics, one must understand the link between genotype (DNA sequence) and phenotype (observable characteristics). Advances in high-throughput genomic sequencing technologies and applications, so-called "-omics," have made genetic sequencing readily available across fields in biology from applications in non-traditional study organisms to precision medicine. Thus, understanding these tools is critical for any biologist, especially those early in their career. This comprehensive review discusses the chronological development of different sequencing methods, the bioinformatics steps to analyzing this data, and social and ethical issues raised by these techniques that must be discussed and evaluated, including anticipatory guides and discussion questions for active engagement in the classroom. Additionally, the Supporting Information includes a case study to apply technical and ethical concepts from the text.

22Metazoan transcriptional regulatory factors (TFs) bind to genomic response elements and 23 assemble with co-regulators into transcriptional regulatory complexes (TRCs) whose 24 composition, structure and activities are gene-, cell-and physiological-context specific. 25Each TRC is a "regulatory logic module," integrating incoming signaling information, 26 which defines context and thereby recruits a distinct combination of co-regulators that 27 together specify outgoing regulatory activity. Analyzing TRCs unique to every context is 28daunting, yet justified by their properties as self-contained regulatory modules. As proof-29 of-concept, we performed a forward genetic screen in C. elegans carrying a synthetic 30 simple response element for nuclear receptor NHR-25 upstream of a fluorescent reporter 31 gene. We isolated independent mutations in uba-2, a component of the sumoylation 32 signaling machinery, and in lir-2, which we demonstrated to be a novel co-regulator, 33interacting with NHR-25 through LxxLL motifs and modulating target gene expression. 34Our studies establish that an unbiased genetic screen readily identifies both afferent and 35 efferent components that specify TRC function, and suggest that screening natural 36 response elements of interest could illuminate molecular mechanisms of both context-37 specificity and transcriptional regulation. 38 39 INTRODUCTION 40