Plasmodium falciparum has evolved resistance to almost all front-line drugs including artemisinin, which threatens malaria control and elimination strategies. Oxidative stress and protein damage responses have emerged as key players in the generation of artemisinin resistance. In this study, we show that PfGCN5, a histone acetyltransferase, binds to the stress-responsive genes in a poised state and regulates their expression under stress conditions. Furthermore, we show that upon artemisinin exposure, genome-wide binding sites for PfGCN5 are increased and it is directly associated with the genes implicated in artemisinin resistance generation like BiP and TRiC chaperone. Interestingly, expression of genes bound by PfGCN5 was found to be upregulated during stress conditions. Moreover, inhibition of PfGCN5 in artemisinin-resistant parasites increases the sensitivity of the parasites to artemisinin treatment indicating its role in drug resistance generation. Together, these findings elucidate the role of PfGCN5 as a global chromatin regulator of stress-responses with a potential role in modulating artemisinin drug resistance and identify PfGCN5 as an important target against artemisinin-resistant parasites.

Circadian clocks regulate the rhythmic expression of thousands of genes underlying the daily oscillations of biological functions. Here, we discuss recent findings showing that circadian clock rhythmic transcriptional outputs rely on additional mechanisms than just clock gene DNA binding, which may ultimately contribute to the plasticity of circadian transcriptional programs.

2 3 4 PfGCN5, a global regulator of stress responsive genes, modulates artemisinin resistance 5 in Plasmodium falciparum 2 25 Abstract26 Plasmodium falciparum has evolved resistance to almost all front-line drugs including 27 artemisinins, which threatens malaria control and elimination strategies. Oxidative stress and 28 protein damage responses have emerged as key players in the generation of artemisinin 29 resistance. In this study, we show that PfGCN5, a histone acetyltransferase, binds to the stress 30 responsive and multi-variant family genes in poised state and regulates their expression under 31 stress conditions. We have also provided biochemical and cellular evidences that PfGCN5 32 regulates stress responsive genes by acetylation of PfAlba3. Furthermore, we show that upon 33 artemisinin exposure, genome-wide binding sites for PfGCN5 are increased and it is directly 34 associated with the genes implicated in artemisinin resistance generation like BiP and TRiC 35 chaperone. Moreover, inhibition of PfGCN5 in artemisinin resistant parasites, Kelch13 36 mutant, K13I543T and K13C580Y (RSA~ 25% and 6%, respectively) reverses the sensitivity 37 of the parasites to artemisinin treatment indicating its role in drug resistance generation.38 Together, these findings elucidate the role of PfGCN5 as a global chromatin regulator of 39 stress-responses with potential role in modulating artemisinin drug resistance, and identify 40 PfGCN5 as an important target against artemisinin resistant parasites. 41 3 42 Author Summary 43 Malaria parasites are constantly adapting to the drugs we used to eliminate them. Thus, when 44 we use the drugs to kill parasites; with time, we select the parasites with the favourable 45 genetic changes. Parasites develop various strategies to overcome exposure to the drugs by 46 exhibiting the stress responses. The changes specific to the drug adapted parasites can be 47 used to understand the mechanism of drug resistance generation. In this study, we have 48 identified PfGCN5 as a global transcriptional regulator of stress responses in Plasmodium 49 falciparum. Inhibition of PfGCN5 reverses the sensitivity of the parasites to the artemisinin 50 drug and identify PfGCN5 as an important target against artemisinin resistant parasites. 51 52 53 54 55 56 57 58 59 4 60 Introduction 61 Malaria is a life threatening infectious disease caused by parasites from the genus 62 Plasmodium, with an estimated 200 million cases worldwide [1]. The Anopheles mosquito 63 serves as a vector for varied species of the human malaria parasite namely P. falciparum, P. 64 vivax, P. ovale, P. malariae and P. knowlesi. Of these five species, P. falciparum causes most 65 lethal form of malaria. The Plasmodium life cycle consists of two phases, sexual and asexual 66 in mosquitoes and humans, respectively. Since Plasmodium completes its life cycle in two 67 different hosts, it requires mechanisms for coordinated modulation of gene expression [2]. An 68 efficient transcriptional and post-transcriptional regulation of gene ex...

Rhythmic gene expression is a hallmark of the circadian rhythm and is essential for driving the rhythmicity of biological functions at the appropriate time of day. Studies over the last few decades have shown that rhythmic food intake (i.e., the time at which organisms eat food during the 24 h day), significantly contributes to the rhythmic regulation of gene expression in various organs and tissues throughout the body. The effects of rhythmic food intake on health and physiology have been widely studied ever since and have revealed that restricting food intake for 8 h during the active phase attenuates metabolic diseases arising from a variety of obesogenic diets. These studies often require the use of controlled methods for timing the delivery of food to animals. This manuscript describes the design and use of a low-cost and efficient system, built in-house for measuring daily food consumption as well as manipulating rhythmic food intake in mice. This system entails the use of affordable raw materials to build cages suited for food delivery, following a user-friendly handling procedure.This system can be used efficiently to feed mice on different feeding regimens such as ad libitum, time-restricted, or arrhythmic schedules, and can incorporate a high-fat diet to study its effect on behavior, physiology, and obesity. A description of how wildtype (WT) mice adapt to the different feeding regimens is provided.

Rhythmic gene expression is a hallmark of the circadian rhythm and is essential for driving the rhythmicity of biological functions at the appropriate time of day. Studies over the last few decades have shown that rhythmic food intake (i.e., the time at which organisms eat food during the 24 h day), significantly contributes to the rhythmic regulation of gene expression in various organs and tissues throughout the body. The effects of rhythmic food intake on health and physiology have been widely studied ever since and have revealed that restricting food intake for 8 h during the active phase attenuates metabolic diseases arising from a variety of obesogenic diets. These studies often require the use of controlled methods for timing the delivery of food to animals. This manuscript describes the design and use of a low-cost and efficient system, built in-house for measuring daily food consumption as well as manipulating rhythmic food intake in mice. This system entails the use of affordable raw materials to build cages suited for food delivery, following a user-friendly handling procedure.This system can be used efficiently to feed mice on different feeding regimens such as ad libitum, time-restricted, or arrhythmic schedules, and can incorporate a high-fat diet to study its effect on behavior, physiology, and obesity. A description of how wildtype (WT) mice adapt to the different feeding regimens is provided.