The accessory Nef protein of HIV and SIV is essential for viral pathogenesis, yet it is perplexing in its multitude of molecular functions. In this review we analyse the structure–function ...relationships of motifs recently proposed to play roles in aspects of Nef modification, signalling and trafficking, and thereby to impinge on the ability of the virus to survive in, and to manipulate, its cellular host. Based on the full‐length structure assembly of HIV Nef, we correlate surface accessibility with secondary structure elements and sequence conservation. Motifs involved in Nef‐mediated CD4 and MHC I downregulation are located in flexible regions of Nef, suggesting that the formation of the transient trafficking complexes involved in these processes depends on the recognition of primary sequences. In contrast, the interaction sites for signalling molecules that contain SH3 domains or the p21‐activated kinases are associated with the well folded core domain, suggesting the recognition of highly structured protein surfaces.
Preterm birth is the leading cause of mortality in newborn infants and can lead to significant neonatal morbidities. Spontaneous preterm birth accounts for at least 50.0% of all preterm births. We ...argue that chronic maternal stress load, which is an important risk factor for spontaneous preterm birth, could be represented by epigenetic signature of several specific genetic loci in the mother’s blood. A literature search was done in PubMed with the following keywords: “DNA methylation,” “epigenetics,” “maternal stress” and “preterm birth” from year 2000 to 2017. We suggest that these genetic loci might be related to vulnerability and hypersensibility of stress response during pregnancy in women with preterm births. The mother’s epi-genetic stress bioprofile was supposed to be a result of chronic maternal stress load since her birth. This epigenetic bioprofile might also be a potential biomarker for spontaneous preterm birth. DNA methylation changes are tissue-specific and human stress response manifests mostly through the central nervous system (CNS). Nevertheless, we found evidence that methylation changes of DNA isolated from blood leucocytes might be a reliable measure of stress-related epigenetic changes that occur in the CNS. Evaluating biological mechanisms through the development of simple assays based on epigenetic changes to measure chronic stress loads in expectant mothers can lead to our ability to prepare more effective measures for the prevention of preterm births, as well as leading to more effective treatment strategies for both expectant mothers and their newborns.
(Headache 2010;50:631‐648)
Adipose tissue is a dynamic neuroendocrine organ that is involved in multiple physiological and pathological processes, and when excessive, results in obesity. Clinical and ...population‐based data suggest that migraine and chronic daily headache are associated with obesity, as estimated by anthropometric indices. In addition, translational and basic science research shows multiple areas of overlap between migraine pathophysiology and the central and peripheral pathways regulating feeding. Specifically, neurotransmittors such as serotonin, peptides such as orexin, and adipocytokines such as adiponectin and leptin have been suggested to have roles in both feeding and migraine. In this article, we first review the definition and ascertainment of obesity. This is followed by a review of the clinical and population‐based studies evaluating the associations between obesity and chronic daily headache and migraine. We then discuss the central and peripheral pathways involved in the regulation of feeding, where it overlaps with migraine pathophysiology, and where future research may be headed in light of these data.
(Headache 2011;51:839‐842)
Significant sex differences exist in migraine and other headache disorders. Several hypotheses have been proposed to explain these differences, including fluctuations in ...sex hormones and receptor binding, genetic factors, differences in exposure to environmental stressors, as well as differences in response to stress and pain perception; but how valid are some of these findings and can we improve the quality of research in this field? It is notable that the preponderance of animal pain studies use male subjects to study a predominantly female disorder. Furthermore, with respect to headache and migraine sex differences, limited data have been derived from animal models. Additionally, although sex differences (based on the categorization of male vs female) may be more routinely evaluated in clinical headache research than in the basic science research, greater attention to potential differences across the life cycle of women (ie, premenopausal vs postmenopausal differences) and menstrual cycle is warranted. In this manuscript we define the differences between “sex” and “gender” and highlight the importance of their application and use in headache research. The enhanced recognition and implementation of attention to sex differences throughout the hormonal and life‐cycle phase in both human and animal research will only help to strengthen and further our understanding of migraine and may help guide the direction of future headache research.
The autoimmune regulator (AIRE) is a transcription factor which is expressed in medullary thymic epithelial cells. It directs the expression of otherwise tissue-specific antigens, which leads to the ...elimination of autoreactive T cells during development. AIRE is modified post-translationally by phosphorylation and ubiquitylation. In this report we connected these modifications. AIRE, which is phosphorylated on two specific residues near its N terminus, then binds to the F-box protein 3 (FBXO3) E3 ubiquitin ligase. In turn, this SCFFBXO3 (SKP1-CUL1-F box) complex ubiquitylates AIRE, increases its binding to the positive transcription elongation factor b (P-TEFb), and potentiates its transcriptional activity. Because P-TEFb is required for the transition from initiation to elongation of transcription, this interaction ensures proper expression of AIRE-responsive tissue-specific antigens in the thymus.
Human immunodeficiency virus type 1 (HIV-1) transcriptional transactivator (Tat) recruits the positive transcription elongation factor b (P-TEFb) to the viral promoter. Consisting of cyclin dependent ...kinase 9 (Cdk9) and cyclin T1, P-TEFb phosphorylates RNA polymerase II and the negative transcription elongation factor to stimulate the elongation of HIV-1 genes. A major fraction of nuclear P-TEFb is sequestered into a transcriptionally inactive 7SK small nuclear ribonucleoprotein (snRNP) by the coordinated actions of the 7SK small nuclear RNA (snRNA) and hexamethylene bisacetamide (HMBA) induced protein 1 (HEXIM1). In this study, we demonstrate that Tat prevents the formation of and also releases P-TEFb from the 7SK snRNP in vitro and in vivo. This ability of Tat depends on the integrity of its N-terminal activation domain and stems from the high affinity interaction between Tat and cyclin T1, which allows Tat to directly displace HEXIM1 from cyclin T1. Furthermore, we find that in contrast to the Tat-independent activation of the HIV-1 promoter, Tat-dependent HIV-1 transcription is largely insensitive to the inhibition by HEXIM1. Finally, primary blood lymphocytes display a reduced amount of the endogenous 7SK snRNP upon HIV-1 infection. All these data are consistent with the model that Tat not only recruits but also increases the active pool of P-TEFb for efficient HIV-1 transcription.
c-Myc promotes cellular proliferation, sensitizes cells to apoptosis and prevents differentiation. It binds cyclin T1 structurally and functionally from the positive transcription elongation factor b ...(P-TEFb). The cyclin-dependent kinase 9 (Cdk9) in P-TEFb then phosporylates the C-terminal domain of RNA polymerase II, which is required for the transition from initiation to elongation of eukaryotic transcription. Inhibiting P-TEFb blocks the transcription of its target genes as well as cellular proliferation and apoptosis induced by c-Myc.
Objective
To examine the independent and joint associations of childhood abuse and intimate partner violence with migraine among pregnant women.
Background
Childhood abuse and intimate partner ...violence have each been associated with migraine headaches in previous studies, but these associations have not been explored among pregnant women.
Methods
A cross‐sectional study was conducted among a cohort of 2970 pregnant women attending prenatal clinics in Lima, Peru. History of childhood abuse (ie, physical or sexual abuse) was assessed using the Childhood Physical and Sexual Abuse Questionnaire. Intimate partner violence (IPV) was assessed using the World Health Organization questionnaire. Migraine classification (including migraine and probable migraine) was based on International Classification of Headache Disorders (ICHD)‐III beta criteria. Multivariable logistic regression analyses were performed to estimate odd ratios (OR) and 95% confidence intervals (95% CI).
Results
The prevalence of any migraine was 33.5% while approximately 70% of participants reported a history of childhood abuse and 36.7% a history of IPV. Women with a history of any childhood abuse had a 38% increased odds of any migraine compared to women with no history of childhood abuse (OR = 1.38; 95% CI 1.15‐1.64). The odds of migraine increased with increasing numbers of experienced childhood abuse events (Ptrend < .001). Additionally, after adjusting for confounders women with a history of IPV had a 43% increased odds of any migraine as compared to women without intimate partner violence (OR = 1.43; 95%CI 1.02‐2.02). Women with a joint positive history of childhood abuse and IPV, as compared with the reference group, had a 88% increased odds of migraine (aOR = 1.88, 95%CI: 1.51‐2.35).
Conclusion
Childhood abuse and IPV are associated with increased odds of migraine in pregnant women. Our findings highlight the importance of screening for abuse among pregnant migraineurs to help guide treatment strategies.
Autoimmune regulator (AIRE) and nuclear factor-κB (NF-κB) are transcription factors (TFs) that direct the expression of individual genes and gene clusters. Bromodomain-containing protein 4 (BRD4) is ...an epigenetic regulator that recognizes and binds to acetylated histones. BRD4 also has been reported to promote interactions between the positive transcription elongation factor b (P-TEFb) and AIRE or P-TEFb and NF-κB subunit p65. Here, we report that AIRE and p65 bind to P-TEFb independently of BRD4. JQ1, a compound that disrupts interactions between BRD4 and acetylated proteins, does not decrease transcriptional activities of AIRE or p65. Moreover, siRNA-mediated inactivation of BRD4 alone or in combination with JQ1 had no effects on AIRE- and NF-κB–targeted genes on plasmids and in chromatin and on interactions between P-TEFb and AIRE or NF-κB. Finally, ChIP experiments revealed that recruitment of P-TEFb to AIRE or p65 to transcription complexes was independent of BRD4. We conclude that direct interactions between AIRE, NF-κB, and P-TEFb result in efficient transcription of their target genes.
The autoimmune regulator is a critical transcription factor for generating central tolerance in the thymus. Recent studies have revealed how the autoimmune regulator targets many otherwise ...tissue-restricted Ag genes to enable negative selection of autoreactive T cells.
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