Acquisition of the spindle assembly checkpoint and its modulation by cell fate and cell size in a chordate embryo.

The spindle assembly checkpoint (SAC) is a surveillance system that preserves genome integrity by delaying anaphase onset until all chromosomes are correctly attached to spindle microtubules. Recruitment of SAC proteins to unattached kinetochores generates an inhibitory signal that prolongs mitotic duration. Chordate embryos are atypical in that spindle defects do not delay mitotic progression during early development, implying that either the SAC is inactive or the cell-cycle target machinery is unresponsive. Here, we show that in embryos of the chordate Phallusia mammillata, the SAC delays mitotic progression from the 8th cleavage divisions. Unattached kinetochores are not recognized by the SAC machinery until the 7th cell cycle, when the SAC is acquired. After acquisition, SAC strength, which manifests as the degree of mitotic lengthening induced by spindle perturbations, is specific to different cell types and is modulated by cell size, showing similarity to SAC control in early Caenorhabditis elegans embryos. We conclude that SAC acquisition is a process that is likely specific to chordate embryos, while modulation of SAC efficiency in SAC proficient stages depends on cell fate and cell size, which is similar to non-chordate embryos.

Totipotency continuity from zygote to early blastomeres: a model under revision.

The mammalian zygote is a totipotent cell that generates all the cells of a new organism through embryonic development. However, if one asks about the totipotency of blastomeres after one or two zygotic divisions, opinions differ. As it is impossible to determine the individual developmental potency of early blastomeres in an intact embryo, experiments of blastomere isolation were conducted in various species, showing that two-cell blastomeres could give rise to a new organism when sister cells were separated. A mainstream interpretation was that each of the sister mammalian blastomeres was equally totipotent. However, reevaluation of those experiments raised some doubts about the real prevalence of cases in which this interpretation could truly be validated. We compiled experiments that tested the individual developmental potency of early mammalian blastomeres in a cell-autonomous way (i.e. excluding nuclear transfer and chimera production). We then confronted the developmental abilities with reported molecular differences between sister blastomeres. The reevaluated observations were at odds with the mainstream view: A viable two-cell embryo can already include one non-totipotent blastomere. We were, thus, led to propose a revised model for totipotency continuity based on the construction of the zygote as a mosaic, which accounts for differential inheritance of totipotency-relevant components between sister blastomeres. This takes place with no preordained mechanisms that would ensure a reproducible partition. This model, which is compatible with the body of data on regulative properties of mammalian early embryos, aims at tempering the rigid interpretation that discounted maternal constraints on totipotency.

The Human 343delT HSPB5 Chaperone Associated with Early-onset Skeletal Myopathy Causes Defects in Protein Solubility.

Mutations of HSPB5 (also known as CRYAB or αB-crystallin), a bona fide heat shock protein and molecular chaperone encoded by the HSPB5 (crystallin, alpha B) gene, are linked to multisystem disorders featuring variable combinations of cataracts, cardiomyopathy, and skeletal myopathy. This study aimed to investigate the pathological mechanisms involved in an early-onset myofibrillar myopathy manifesting in a child harboring a homozygous recessive mutation in HSPB5, 343delT. To study HSPB5 343delT protein dynamics, we utilize model cell culture systems including induced pluripotent stem cells derived from the 343delT patient (343delT/343delT) along with isogenic, heterozygous, gene-corrected control cells (WT KI/343delT) and BHK21 cells, a cell line lacking endogenous HSPB5 expression. 343delT/343delT and WT KI/343delT-induced pluripotent stem cell-derived skeletal myotubes and cardiomyocytes did not express detectable levels of 343delT protein, contributable to the extreme insolubility of the mutant protein. Overexpression of HSPB5 343delT resulted in insoluble mutant protein aggregates and induction of a cellular stress response. Co-expression of 343delT with WT prevented visible aggregation of 343delT and improved its solubility. Additionally, in vitro refolding of 343delT in the presence of WT rescued its solubility. We demonstrate an interaction between WT and 343delT both in vitro and within cells. These data support a loss-of-function model for the myopathy observed in the patient because the insoluble mutant would be unavailable to perform normal functions of HSPB5, although additional gain-of-function effects of the mutant protein cannot be excluded. Additionally, our data highlight the solubilization of 343delT by WT, concordant with the recessive inheritance of the disease and absence of symptoms in carrier individuals.

Heat Shock Proteins and Maternal Contribution to Oogenesis and Early Embryogenesis.

Early embryos develop from fertilized eggs using materials that are stored during oocyte growth and which can be defined as maternal contribution (molecules, factors, or determinants). Several heat shock proteins (HSPs) and the heat shock transcriptional factor (HSF) are part of the maternal contribution that is critical for successful embryogenesis and reproduction. A maternal role for heat shock-related genes was mainly demonstrated in genetic experimental organisms (e.g., fly, nematode, mouse). Nowadays, an increasing number of "omics" data are produced from a large panel of organisms implementing a catalog of maternal and/or embryonic HSPs and HSFs. However, for most of them, it remains to better understand their potential roles in this context. Existing and future genome-wide screens mainly set up to create loss-of-function are likely to improve this situation. This chapter will discuss available data from various experimental organisms following the developmental steps from egg production to early embryogenesis.

Glutathione-dependent reductive stress triggers mitochondrial oxidation and cytotoxicity.

To investigate the effects of the predominant nonprotein thiol, glutathione (GSH), on redox homeostasis, we employed complementary pharmacological and genetic strategies to determine the consequences of both loss- and gain-of-function GSH content in vitro. We monitored the redox events in the cytosol and mitochondria using reduction-oxidation sensitive green fluorescent protein (roGFP) probes and the level of reduced/oxidized thioredoxins (Trxs). Either H(2)O(2) or the Trx reductase inhibitor 1-chloro-2,4-dinitrobenzene (DNCB), in embryonic rat heart (H9c2) cells, evoked 8 or 50 mV more oxidizing glutathione redox potential, E(hc) (GSSG/2GSH), respectively. In contrast, N-acetyl-L-cysteine (NAC) treatment in H9c2 cells, or overexpression of either the glutamate cysteine ligase (GCL) catalytic subunit (GCLC) or GCL modifier subunit (GCLM) in human embryonic kidney 293 T (HEK293T) cells, led to 3- to 4-fold increase of GSH and caused 7 or 12 mV more reducing E(hc), respectively. This condition paradoxically increased the level of mitochondrial oxidation, as demonstrated by redox shifts in mitochondrial roGFP and Trx2. Lastly, either NAC treatment (EC(50) 4 mM) or either GCLC or GCLM overexpression exhibited increased cytotoxicity and the susceptibility to the more reducing milieu was achieved at decreased levels of ROS. Taken together, our findings reveal a novel mechanism by which GSH-dependent reductive stress triggers mitochondrial oxidation and cytotoxicity.

Proteostasis and REDOX state in the heart.

Force-generating contractile cells of the myocardium must achieve and maintain their primary function as an efficient mechanical pump over the life span of the organism. Because only half of the cardiomyocytes can be replaced during the entire human life span, the maintenance strategy elicited by cardiac cells relies on uninterrupted renewal of their components, including proteins whose specialized functions constitute this complex and sophisticated contractile apparatus. Thus cardiac proteins are continuously synthesized and degraded to ensure proteome homeostasis, also termed "proteostasis." Once synthesized, proteins undergo additional folding, posttranslational modifications, and trafficking and/or become involved in protein-protein or protein-DNA interactions to exert their functions. This includes key transient interactions of cardiac proteins with molecular chaperones, which assist with quality control at multiple levels to prevent misfolding or to facilitate degradation. Importantly, cardiac proteome maintenance depends on the cellular environment and, in particular, the reduction-oxidation (REDOX) state, which is significantly different among cardiac organelles (e.g., mitochondria and endoplasmic reticulum). Taking into account the high metabolic activity for oxygen consumption and ATP production by mitochondria, it is a challenge for cardiac cells to maintain the REDOX state while preventing either excessive oxidative or reductive stress. A perturbed REDOX environment can affect protein handling and conformation (e.g., disulfide bonds), disrupt key structure-function relationships, and trigger a pathogenic cascade of protein aggregation, decreased cell survival, and increased organ dysfunction. This review covers current knowledge regarding the general domain of REDOX state and protein folding, specifically in cardiomyocytes under normal-healthy conditions and during disease states associated with morbidity and mortality in humans.

Lack of maternal Heat Shock Factor 1 results in multiple cellular and developmental defects, including mitochondrial damage and altered redox homeostasis, and leads to reduced survival of mammalian oocytes and embryos.

Heat Shock Factor 1 (HSF1) is a transcription factor whose loss of function results in the inability of Hsf1(-/-) females to produce viable embryos, as a consequence of early developmental arrest. We previously demonstrated that maternal HSF1 is required in oocytes to regulate expression of chaperones, in particular Hsp90alpha, and is essential for the progression of meiotic maturation. In the present work, we used comparative morphological and biochemical analytic approaches to better understand how Hsf1(-/-) oocytes undergo irreversible cell death. We found that the metaphase II arrest in mature oocytes, cortical granule exocytosis and formation of pronuclei in zygotes were all impaired in Hsf1(-/-) mutants. Although oogenesis generated fully grown oocytes in follicles, intra-ovarian Hsf1(-/-) oocytes displayed ultrastructural abnormalities and contained dysfunctional mitochondria as well as elevated oxidant load. Finally, the apoptotic effector, caspase-3, was activated in most mutant oocytes and embryos, reflecting their commitment to apoptosis. In conclusion, our study shows that early post-ovulation events are particularly sensitive to oxidant insult, which abrogates the developmental competence of HSF1-depleted oocytes. They also reveal that Hsf1 knock-out mice constitute a genetic model that can be used to evaluate the importance of redox homeostasis in oocytes.

Heat shock transcription factor 1 localizes to sex chromatin during meiotic repression.

Heat shock factor 1 (HSF1) is an important transcription factor in cellular stress responses, cancer, aging, and developmental processes including gametogenesis. Disruption of Hsf1, together with another HSF family member, Hsf2, causes male sterility and complete lack of mature sperm in mice, but the specific role of HSF1 in spermatogenesis has remained unclear. Here, we show that HSF1 is transiently expressed in meiotic spermatocytes and haploid round spermatids in mouse testis. The Hsf1(-/-) male mice displayed regions of seminiferous tubules containing only spermatogonia and increased morphological abnormalities in sperm heads. In search for HSF1 target genes, we identified 742 putative promoters in mouse testis. Among them, the sex chromosomal multicopy genes that are expressed in postmeiotic cells were occupied by HSF1. Given that the sex chromatin mostly is repressed during and after meiosis, it is remarkable that HSF1 directly regulates the transcription of sex-linked multicopy genes during postmeiotic repression. In addition, our results show that HSF1 localizes to the sex body prior to the meiotic divisions and to the sex chromocenter after completed meiosis. To the best of our knowledge, HSF1 is the first known transcription factor found at the repressed sex chromatin during meiosis.

Daily variations of Ostreopsis cf. ovata abundances in NW Mediterranean Sea.

Ostreopsis cf. ovata is a benthic dinoflagellate very common in tropical and temperate coastal areas, particularly in the Mediterranean Sea. This species is also found in the plankton, i.e. swimming in the water column or in aggregates floating at the sea surface. The potential links between the planktonic and benthic populations influencing their relative distribution in the water column and attached to the benthic substrate are poorly understood. To shed light on this question, a high-frequency temporal monitoring was conducted in the Villefranche bay (France) to determine the abundance of (1) epibenthic cells attached to macroalgae, (2) planktonic cells in the water column and (3) cells in aggregates floating at the sea water surface (hereafter, referred to sea surface cells) . This monitoring was realized over 3 consecutive years (2018, 2019 and 2020) and at different phases of the bloom (exponential phase - 2020, peak - 2019 and decline phase - 2018). Strong variations in benthic and planktonic O. cf. ovata abundances were observed over the 24 h sampling cycles conducted in three consecutive years. The three populations, planktonic, benthic and sea surface cells, exhibited the highest numbers during the day (light) hours and lowest values at night in 2018 and 2019. In 2020, however, benthic abundances did not differ significantly between light and dark periods. Moreover, epibenthic cells abundances peaked in the morning, followed by the peak of the cells in the plankton and in the surface aggregates during the afternoon. Monitoring of O. cf. ovata is often based on a single sampling per day without precise indications of sampling time and shows great variability in O. cf. ovata abundances. Our observations of daily variations in cell abundances along the water column clearly indicate that time and water column depth of sampling constitute a great source of variability and have to be considered when designing new monitoring strategies to reduce variability and to harmonize data acquisition and international comparisons.

The Spindle Assembly Checkpoint Functions during Early Development in Non-Chordate Embryos.

In eukaryotic cells, a spindle assembly checkpoint (SAC) ensures accurate chromosome segregation, by monitoring proper attachment of chromosomes to spindle microtubules and delaying mitotic progression if connections are erroneous or absent. The SAC is thought to be relaxed during early embryonic development. Here, we evaluate the checkpoint response to lack of kinetochore-spindle microtubule interactions in early embryos of diverse animal species. Our analysis shows that there are two classes of embryos, either proficient or deficient for SAC activation during cleavage. Sea urchins, mussels, and jellyfish embryos show a prolonged delay in mitotic progression in the absence of spindle microtubules from the first cleavage division, while ascidian and amphioxus embryos, like those of Xenopus and zebrafish, continue mitotic cycling without delay. SAC competence during early development shows no correlation with cell size, chromosome number, or kinetochore to cell volume ratio. We show that SAC proteins Mad1, Mad2, and Mps1 lack the ability to recognize unattached kinetochores in ascidian embryos, indicating that SAC signaling is not diluted but rather actively silenced during early chordate development.

Heat shock transcription factor 2 is not essential for embryonic development, fertility, or adult cognitive and psychomotor function in mice.

Members of the heat shock factor (HSF) family are evolutionarily conserved regulators that share a highly homologous DNA-binding domain. In mammals, HSF1 is the main factor controlling the stress-inducible expression of Hsp genes while the functions of HSF2 and HSF4 are less clear. Based on its developmental profile of expression, it was hypothesized that HSF2 may play an essential role in brain and heart development, spermatogenesis, and erythroid differentiation. To directly assess this hypothesis and better understand the underlying mechanisms that require HSF2, we generated Hsf2 knockout mice. Here, we report that Hsf2(-/-) mice are viable and fertile and exhibit normal life span and behavioral functions. We conclude that HSF2, most probably because its physiological roles are integrated into a redundant network of gene regulation and function, is dispensable for normal development, fertility, and postnatal psychomotor function.

Single-cell protein analysis of a single mouse embryo by two-dimensional capillary electrophoresis.

The characterization of protein expression from a single-cell mouse embryo using two-dimensional capillary electrophoresis (2D-CE) is described. These zygotes were obtained from Hsf1 gene knockout mice. Single zygotes were lysed off-column and proteins were fluorescently labeled using the fluorogenic dye 3-(2-furoyl)quinoline-2-carboxaldehyde (FQ). After injection, analytes were separated first according to molecular weight using capillary sieving electrophoresis (CSE) and then by micellar electrokinetic capillary chromatography (MEKC) to obtain protein expression fingerprints. Analytes were detected in a sheath flow cuvette using laser-induced fluorescence. In a 1-h 2D-CE separation, over 100 components were resolved with a spot capacity of 380.

Characterization of the Cardiac Overexpression of HSPB2 Reveals Mitochondrial and Myogenic Roles Supported by a Cardiac HspB2 Interactome.

Small Heat Shock Proteins (sHSPs) are molecular chaperones that transiently interact with other proteins, thereby assisting with quality control of proper protein folding and/or degradation. They are also recruited to protect cells from a variety of stresses in response to extreme heat, heavy metals, and oxidative-reductive stress. Although ten human sHSPs have been identified, their likely diverse biological functions remain an enigma in health and disease, and much less is known about non-redundant roles in selective cells and tissues. Herein, we set out to comprehensively characterize the cardiac-restricted Heat Shock Protein B-2 (HspB2), which exhibited ischemic cardioprotection in transgenic overexpressing mice including reduced infarct size and maintenance of ATP levels. Global yeast two-hybrid analysis using HspB2 (bait) and a human cardiac library (prey) coupled with co-immunoprecipitation studies for mitochondrial target validation revealed the first HspB2 "cardiac interactome" to contain many myofibril and mitochondrial-binding partners consistent with the overexpression phenotype. This interactome has been submitted to the Biological General Repository for Interaction Datasets (BioGRID). A related sHSP chaperone HspB5 had only partially overlapping binding partners, supporting specificity of the interactome as well as non-redundant roles reported for these sHSPs. Evidence that the cardiac yeast two-hybrid HspB2 interactome targets resident mitochondrial client proteins is consistent with the role of HspB2 in maintaining ATP levels and suggests new chaperone-dependent functions for metabolic homeostasis. One of the HspB2 targets, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), has reported roles in HspB2 associated phenotypes including cardiac ATP production, mitochondrial function, and apoptosis, and was validated as a potential client protein of HspB2 through chaperone assays. From the clientele and phenotypes identified herein, it is tempting to speculate that small molecule activators of HspB2 might be deployed to mitigate mitochondrial related diseases such as cardiomyopathy and neurodegenerative disease.

Heat shock factor 1 and heat shock proteins: Critical partners in protection against acute cell injury.

OBJECTIVE: Life-threatening conditions cause severe changes in the organization and conformation of macromolecules, creating urgent requirements for protein repair to ensure survival. As molecular chaperones, heat shock proteins (HSP) that have specialized functions in protein folding are now well established to restore homeostasis in cells and organisms. Augmentation of HSP synthesis is tightly regulated by stress-inducible heat shock factors (HSF), which are part of a transcriptional signaling cascade with both positive (e.g., HSP) and negative (e.g., proinflammatory cytokines) properties. In this review, we discuss the biological roles and mechanisms of HSP-mediated protection in pathophysiologic conditions (ischemia, sepsis, and preeclampsia) and the regulation for stress-dependent HSP synthesis and speculate about future applications for harnessing HSF and HSP partners as cytoprotective agents. DATA SOURCES: Reactive oxygen species are major pathogenic factors in cell death pathways (e.g., necrosis, apoptosis), in part, because of proteotoxic effects. In intact organisms, forced overexpression of HSP per se affords effective counterbalance against ischemia challenges (e.g., heart and brain) and systemic conditions (e.g., sepsis). Besides stressful conditions, gene-targeting studies have uncovered new functions for heat shock transcription factors (e.g., maintenance of intrauterine pregnancy) in mammals. In parallel, pharmacologic studies using small molecules are paving the way for future prospects to exploit the beneficial properties of HSP, albeit an important but presently elusive goal. CONCLUSIONS: Together, HSF and HSP partners are attractive targets in therapeutic strategies designed to stimulate endogenous protective mechanisms against deleterious consequences of oxidative stress. With further technological advances, it is anticipated that the spotlight on HSP, alone or in combination with other stress response pathways, could, ultimately, reduce injury and accelerate functional recovery of susceptible organs in living organisms including humans.

Differential heat shock gene hsp70-1 response to toxicants revealed by in vivo study of lungs in transgenic mice.

Members of heat shock proteins (Hsp70) family have been considered to respond to a large variety of stressful conditions. But it was suggested that, in pulmonary cells, Hsp response depends more closely on the type of stimulus. The lungs are critical organs potentially subjected to air pollution affecting respiratory function and, therefore, these organs are of particular interest with regard to the stress response. To investigate the stress dependence of Hsp70 response in lungs, we created transgenic mice where the firefly luciferase reporter gene is under the control of the murine hsp70-1 promoter and exposed them to different sublethal toxic conditions. For each condition, the level of transgene induction and pulmonary toxicity were assessed. We found that hsp70-1 promoter was stimulated by heat shock and cadmium but not by ozone, paraquat, and parathion, even if these chemicals induced respiratory distress and lung inflammation. Similar observations were made when expression of the endogenous hsp70-1 gene was analyzed, indicating that our transgenic model was accurately detecting hsp70-1 induction. Thereby, it appeared that hsp70-1 response is selective and depends on signaling pathways triggered by the toxicants rather than by their pathologic toxicity per se. Furthermore, because all the chemicals used in our study have been previously described to increase the level of oxidative stress, it indicates that there is no direct and simple correlation between hsp70-1 response and the level of oxidative stress, but more specific oxidative patterns should be involved in Hsp regulation.

[When the mother further impacts the destiny of her offspring: maternal effect mutations]. / Quand la mère est plus que responsable du devenir de sa progéniture: les mutations à effet maternel.

Genes affected by maternal effect mutations encode maternal factors (transcripts, proteins) which are normally stored in oocytes and used by the embryos after fertilization. Although females bearing this type of mutation are viable and appear to be normal, embryonic development and survival of their offspring are compromised. Although maternal effect mutations are well known in lower organisms, such as drosophila or zebrafish, several examples have been only quite recently reported in mammals (Dnmt, Hsf1 and Mater). These studies provide new insights on the aspects of embryonic development directly controlled by maternal factors brought by the oocytes.

Chaperones and cardiac misfolding protein diseases.

Cardiomyocytes are best known for their spontaneous beating activity, large cell size, and low regenerative capacity during adulthood. The mechanical activity of cardiomyocytes depends on a sophisticated contractile apparatus comprised of sarcomeres whose rhythmic contraction relies on Ca(2+) transients with a high level of energy consumption. Hence the proper folding and assembly of the sarcomeric and other accessory proteins involved in those diverse functions (i.e., structural, mechanical, energy exchange and production) is critical for muscle mechanics. Chaperone proteins assist other polypeptides to reach their proper conformation, activity and/or location. Consequently, chaperone-like functions are important for the healthy heart but assume greater relevance during cardiac diseases when such chaperone proteins are recruited: 1) to protect cardiac cells against adverse effects during the pathological transition, and 2) to mitigate certain pathogenic mechanisms per se. Protein misfolding is observed as a consequence of inappropriate intracellular environment with acquired conditions (e.g., ischemia/reperfusion and redox imbalance) or because of mutations, which can modify primary to quaternary protein structures. In this review, we discuss the importance of cardiac chaperones while emphasizing the genetic origin (modification of gene/protein sequence) of cardiac protein misfolding and their consequences on the cardiomyocytes leading to organ dysfunction and failure.

Aggregate-prone R120GCRYAB triggers multifaceted modifications of the thioredoxin system.

AIMS: The human mutation R120G in the αB-crystallin (CRYAB) causes a multisystemic disease that is characterized by hypertrophic cardiomyopathy and cytoplasmic protein aggregates. In transgenic mice, human R120GCRYAB (hR120GTg) expression in heart sequentially modifies the REDOX status, in part by the activation of the nuclear factor, erythroid derived 2, like 2 (Nrf2). Thioredoxin system (TS) components are NRF2 target genes, so it could be hypothesized that TS was affected in hR120GTg mice. RESULTS: Transgenic hearts overexpressed thioredoxin 1 (Trx1), which was identified by isotope coded affinity tag-mass spectrometry, among hundreds of peptides displaying an increased reduced/oxidized ratio. Coupled to this higher level of reduced cysteines, the activity of thioredoxin reductase 1 (TrxR1) was augmented by 2.5-fold. Combining mutiple experimental approaches, the enzymatic regulation of TrxR1 by a histone deacetylase 3 (HDAC3)-dependent level of acetylation was confirmed. In vitro and in vivo functional tests established that TrxR1 activity is required to mitigate aggregate development, and this could be mediated by Bcl-2-associated athanogene 3 (BAG3) as a potential TS substrate. INNOVATION AND CONCLUSIONS: This study uncovers the compartmentalized changes and the involvement of TS in the cardiac stress response elicited by misfolded proteins such as R120GCRYAB. Our work suggests that R120GCRYAB triggers a defensive pathway acting through the newly identified interacting partners HDAC3, TrxR1, and BAG3 to counter aggregate growth. Therefore, those interactors may function as modifier genes contributing to the variable onset and expressivity of such human diseases. Furthermore, our work underscores the potential organismal effects of pharmacological interventions targeting TS and HDAC.

Heat shock factor 2 is a stress-responsive mediator of neuronal migration defects in models of fetal alcohol syndrome.

Fetal alcohol spectrum disorder (FASD) is a frequent cause of mental retardation. However, the molecular mechanisms underlying brain development defects induced by maternal alcohol consumption during pregnancy are unclear. We used normal and Hsf2-deficient mice and cell systems to uncover a pivotal role for heat shock factor 2 (HSF2) in radial neuronal migration defects in the cortex, a hallmark of fetal alcohol exposure. Upon fetal alcohol exposure, HSF2 is essential for the triggering of HSF1 activation, which is accompanied by distinctive post-translational modifications, and HSF2 steers the formation of atypical alcohol-specific HSF1-HSF2 heterocomplexes. This perturbs the in vivo binding of HSF2 to heat shock elements (HSEs) in genes that control neuronal migration in normal conditions, such as p35 or the MAPs (microtubule-associated proteins, such as Dclk1 and Dcx), and alters their expression. In the absence of HSF2, migration defects as well as alterations in gene expression are reduced. Thus, HSF2, as a sensor for alcohol stress in the fetal brain, acts as a mediator of the neuronal migration defects associated with FASD.