Epitranscriptomic RNA modifications can regulate mRNA function; however, there is a major gap in our understanding of the biochemical mechanisms mediating their effects. Here, we develop a chemical proteomics approach relying upon photo-cross-linking with synthetic diazirine-containing RNA probes and quantitative proteomics to profile RNA-protein interactions regulated by N-methyladenosine (mA), the most abundant internal modification in eukaryotic RNA. In addition to identifying YTH domain-containing proteins and ALKBH5, known interactors of this modification, we find that FMR1 and LRPPRC, two proteins associated with human disease, "read" this modification. Surprisingly, we also find that mA disrupts RNA binding by the stress granule proteins G3BP1/2, USP10, CAPRIN1, and RBM42. Our work provides a general strategy for interrogating the interactome of RNA modifications and reveals the biochemical mechanisms underlying mA function in the cell.

To better understand temperature's role in the interaction between local evolutionary adaptation and physiological plasticity, we investigated acclimation effects on metabolic performance and thermal tolerance among natural Fundulus heteroclitus (small estuarine fish) populations from different thermal environments. Fundulus heteroclitus populations experience large daily and seasonal temperature variations, as well as local mean temperature differences across their large geographical cline. In this study, we use three populations: one locally heated (32°C) by thermal effluence (TE) from the Oyster Creek Nuclear Generating Station, NJ, and two nearby reference populations that do not experience local heating (28°C). After acclimation to 12 or 28°C, we quantified whole-animal metabolic (WAM) rate, critical thermal maximum (CT max ) and substrate-specific cardiac metabolic rate (CaM, substrates: glucose, fatty acids, lactate plus ketones plus ethanol, and endogenous (i.e. no added substrates)) in approximately 160 individuals from these three populations. Populations showed few significant differences due to large interindividual variation within populations. In general, for WAM and CT max , the interindividual variation in acclimation response (log 2 ratio 28/12°C) was a function of performance at 12°C and order of acclimation (12–28°C versus 28–12°C). CT max and WAM were greater at 28°C than 12°C, although WAM had a small change (2.32-fold) compared with the expectation for a 16°C increase in temperature (expect 3- to 4.4-fold). By contrast, for CaM, the rates when acclimatized and assayed at 12 or 28°C were nearly identical. The small differences in CaM between 12 and 28°C temperature were partially explained by cardiac remodeling where individuals acclimatized to 12°C had larger hearts than individuals acclimatized to 28°C. Correlation among physiological traits was dependent on acclimation temperature. For example, WAM was negatively correlated with CT max at 12°C but positively correlated at 28°C. Additionally, glucose substrate supported higher CaM than fatty acid, and fatty acid supported higher CaM than lactate, ketones and alcohol (LKA) or endogenous. However, these responses were highly variable with some individuals using much more FA than glucose. These findings suggest interindividual variation in physiological responses to temperature acclimation and indicate that additional research investigating interindividual may be relevant for global climate change responses in many species.

18Variation in tissue-specific metabolism between species and among individuals is thought to be 19 adaptively important; however, understanding this evolutionary relationship requires reliably 20 measuring this trait in many individuals. In most higher organisms, tissue specificity is important 21 because different organs (heart, brain, liver, muscle) have unique ecologically adaptive roles. 22Current technology and methodology for measuring tissue-specific metabolism is costly and 23 limited by throughput capacity and efficiency. Presented here is the design for a flexible and 24 cost-effective high-throughput micro-respirometer (HTMR) optimized to measure small 25 biological samples. To verify precision and accuracy, substrate specific metabolism was 26 measured in heart ventricles isolated from a small teleost, Fundulus heteroclitus, and in yeast 27 (Saccharomyces cerevisiae). Within the system, results were reproducible between chambers and 28 over time with both teleost hearts and yeast. Additionally, metabolic rates and allometric scaling 29 relationships in Fundulus agree with previously published data measured with lower-throughput 30 equipment. This design reduces cost, but still provides an accurate measure of metabolism in 31 small biological samples. This will allow for high-throughput measurement of tissue metabolism 32 that can enhance understanding of the adaptive importance of complex metabolic traits. 33

Metabolic rate is often measured as a phenotype in evolutionary genetics, among other fields including many facets of physiology, behavior, and ecology, because it impacts organismal fitness, is repeatable and heritable, and is responsive to numerous environmental variables. Aquatic respirometry, a method used to measure metabolic rate, has allowed key questions in these fields to be investigated, namely: (1) why do individuals from the same population exhibit up to 3-fold differences in metabolic rate, (2) how does metabolic rate change during an individual's lifetime, and ( 3) what metabolic rate is advantageous in a specific environment? Current respirometry studies often suffer from small sample sizes and rely on low throughput approaches to measure metabolic rate, making it difficult to answer these and other relevant ecological and evolutionary questions due to lack of power, failure to capture true biological variation, and confounding variables, like time, that are introduced due to limitations in methodology.Here we describe a scalable high-throughput intermittent flow respirometer (HIFR) design and use it to measure the metabolic rates of 19 aquatic animals in one night while reducing equipment costs and time by more than 50%.

7 8 Keywords: Fundulus heteroclitus, evolutionary analysis, standard metabolic rate 9 ABSTRACT 10 Metabolic rate is often measured as a phenotype in evolutionary genetics studies because it 11 impacts organismal fitness, is repeatable and heritable, and is responsive to numerous 12 environmental variables. Despite a wide body of literature about metabolic rates, key questions 13 remain unanswered: 1) why do individuals from the same population exhibit up to three fold 14 differences in metabolic rate, 2) how does metabolic rate change during an individual's lifetime, 15 and 3) what metabolic rate is advantageous in a specific environment? Current low throughput 16 approaches to measure metabolic rate make it difficult to answer these and other relevant 17 ecological and evolutionary questions that require a much larger sample size. Here we describe a 18 scalable high-throughput intermittent flow respirometer (HIFR) design and use it to measure the 19 metabolic rates of 20 aquatic animals simultaneously while reducing equipment costs and time 20 by more than 50%. INTRODUCTION22 Metabolic rate is often measured as a phenotype in evolutionary genetics studies because it is 23 known to impact organismal fitness, is repeatable and heritable, and is affected by a variety of 24 environmental variables (1-5). The relationship between metabolic rate and a variable of interest, 25 such as temperature, oxygen availability, or toxicant exposure, has been investigated frequently, 26 which has led to a rich literature on metabolic rates in many species (7)(8)(9)(10)(11). Despite this wide 27 body of literature, key questions about metabolic rates remain unanswered including 1) why do 28 individuals from the same population exhibit up to three fold differences in metabolic rate under 29 similar acclimation conditions and activity levels, 2) how does metabolic rate change during an 30 individual's lifetime, and 3) what metabolic rate is advantageous in a specific environment (7)? 31 32 33 Flow through respirometry, intermittent-flow respirometry (IFR), and closed respirometry are 34 techniques used to measure metabolic rates in terrestrial and aquatic organisms. Flow through 35 respirometry is achieved by measuring the amount of oxygen entering and leaving a chamber 36 relative to the flow rate of air or water through the chamber (12). In IFR the respirometer cycles 37 between open and closed periods. During open periods the chamber is flushed to remove waste 38 and oxygen is replenished and during closed periods the animal is using oxygen sealed in the 39 chamber ( Fig. 1) (12, 13). Closed respirometry places an organism in a sealed chamber of known 40 volume and measures oxygen or carbon dioxide partial pressures at multiple time points 41 throughout the trial. The sealed chamber during closed respirometry may result in the 42 accumulation of nitrogenous waste and carbon dioxide, which can increase stress, and may cause 43 loss of equilibrium (LOE) in aquatic organisms (14).44 Flow-through respirometry and IFR methods may b...