Gustatory dysfunction and long COVID in Chinese patients with COVID-19: A 6-month follow-up study.

AIMS: To evaluate long COVID of gustatory dysfunction and the associated risk factors regarding onset and recovery in Chinese patients. METHODS: We conducted a cross-sectional study of patients with SARS-CoV-2 Omicron infection at Changxing Mobile Cabin Hospital in Shanghai, China, from March to May 2022. A prospective follow-up of patients with gustatory dysfunction was conducted at 6 months after discharge. RESULTS: In total, 18.48% (241/1304) reported gustatory dysfunction. The 6-month follow-up response rate was 89.63% (216/241) and 74.02% recovered their taste sense within 1-3 weeks. A total of 20.37% of patients (44/216) presented with long COVID. Symptoms persisted for 12 patients (5.56%) after 6 months. Having multiple taste impairments (OR, 2.364; 95% CI, 1.286-4.348; p = 0.006) was associated with a higher risk of gustatory dysfunction with long COVID. Having received a COVID-19 vaccine booster was positively associated with taste sensation recovery (HR, 1.344; 95% CI, 1.012-1.785; p = 0.041). CONCLUSIONS: About 20.37% of patients with COVID-19 might develop long COVID of gustatory dysfunction and 5.56% with persisting changes in their sense of taste. Most patients recovered taste sensations within 1-3 weeks after COVID-19 symptom onset and receiving a booster shot of the COVID-19 vaccine presented a protective effect on the taste sensation recovery.

Machine Learning-Based Prediction of Functional Disability: a Cohort Study of Japanese Older Adults in 2013-2019.

BACKGROUND: It is important to identify older adults at high risk of functional disability and to take preventive measures for them at an early stage. To our knowledge, there are no studies that predict functional disability among community-dwelling older adults using machine learning algorithms. OBJECTIVE: To construct a model that can predict functional disability over 5 years using basic machine learning algorithms. DESIGN: A cohort study with a mean follow-up of 5.4 years. PARTICIPANTS: We used data from the Japan Gerontological Evaluation Study, which involved 73,262 people aged ≥ 65 years who were not certified as requiring long-term care. The baseline survey was conducted in 2013 in 19 municipalities. MAIN MEASURES: We defined the onset of functional disability as the new certification of needing long-term care that was ascertained by linking participants to public registries of long-term care insurance. All 183 candidate predictors were measured by self-report questionnaires. KEY RESULTS: During the study period, 16,361 (22.3%) participants experienced the onset of functional disability. Among machine learning-based models, ridge regression (C statistic = 0.818) and gradient boosting (0.817) effectively predicted functional disability. In both models, we identified age, self-rated health, variables related to falls and posture stabilization, and diagnoses of Parkinson's disease and dementia as important features. Additionally, the ridge regression model identified the household characteristics such as the number of members, income, and receiving public assistance as important predictors, while the gradient boosting model selected moderate physical activity and driving. Based on the ridge regression model, we developed a simplified risk score for functional disability, and it also indicated good performance at the cut-off of 6/7 points. CONCLUSIONS: Machine learning-based models showed effective performance prediction over 5 years. Our findings suggest that measuring and adding the variables identified as important features can improve the prediction of functional disability.

Analysis of the Analgesic Effect, Emotion, and Safety of Esketamine in Cesarean Section Analgesia for Puerperae.

Objective: This retrospective study aimed to evaluate the effectiveness and safety of esketamine as an analgesic during cesarean section procedures. Methods: 102 puerperae undergoing cesarean section were divided into a control group and an esketamine (SK) group. Various parameters, including HR, MAP, and postoperative pain, were analyzed. Blood gas analysis and Apgar scores were assessed in neonates. Postoperative depression and satisfaction were evaluated in puerperae. Drug concentrations were measured using liquid-phase tandem mass spectrometry. Results: No significant differences in dimension levels were observed between the two groups (P > .05). However, the SK group showed better HR and MAP indicators at various time points, less postoperative pain, and better mental well-being on postpartum days 1, 3, and 7 (P < .05). Adverse reaction rates were similar between groups (P > .05), but postoperative satisfaction was significantly different (P = .027). Neonatal outcomes did not differ significantly (P > .05). In the SK group, SK2 and SK3 groups had better results compared to SK1 (P < .05). Conclusion: Esketamine during cesarean section stabilized vital signs, reduced pain, and improved well-being in puerperae without affecting newborns. Optimal dosage: 30 µg/kg/h esketamine, 15 ng/kg/h sufentanil.

The Application Value of Esketamine and Dexmedetomidine in Preventing Postoperative Delirium and Hyperalgesia in Elderly Patients with Thoracic Anesthesia.

Objective: Our aim was to evauate the application value of esesketamine and dexmedetomidine in preventing postoperative hyperalgesia in elderly patients who received thoracic anesthesia. Methods: A total of 94 elderly patients who underwent thoracic anesthesia in Sanmen People's Hospital from January 2021 to October 2022 were selected and divided into a dexmedetomidine group (n = 47) and an esketamine group (n = 47) by the random number table method. All patients were continuously received intravenous (IV) remifentanil. In the dexmedetomidine group, dexmedetomidine 0.7 µg/kg was administered IV, followed by 0.2 to 0.5 µg/kg/h to maintain anesthesia, while in the esketamine group, esketamine 0.5 mg/kg was given IV 20 min after induction of anesthesia was completed. Results: Visual analogue scale (VAS) scores in the esketamine group were lower than in the dexmedetomidine group at 1, 6, 12 and 24 h postoperatively (P < .05), and Ramsay sedation scores were not statistically different from those in the dexmedetomidine group (P > .05). At 3 d postoperatively, the Mini-Mental State Examination (MMSE) scores in the dexmedetomidine group were lower than 1 d preoperatively; at 5 d postoperatively, the negative mood and Pittsburgh Sleep Quality Index (PSQI) scores were significantly higher in both groups than 1 d preoperatively; at 14 d postoperatively, the PSQI scores were higher in both groups than 1 d preoperatively, and there was no statistical difference between the negative mood scores at 1 d before surgery (P > .05). At 5 d postoperatively in the esketamine group, the negative mood scores were lower than in the dexmedetomidine group at 5 d postoperatively and the PSQI scores at 5 and 14 d postoperatively were lower than in the dexmedetomidine group (P < .05). Conclusion: Both esketamine and dexmedetomidine can be used to prevent postoperative delirium and nociceptive hypersensitivity after anesthesia in elderly patients with thoracic surgery. However, esketamine is superior to dexmedetomidine in analgesic effect, improvement of negative mood and sleep and stabilization of intraoperative hemodynamics, leading to better effect in preventing delirium and hyperalgesia after anesthesia.

FOXO1 regulates VEGFA expression and promotes angiogenesis in healing wounds.

Angiogenesis is a critical aspect of wound healing. We investigated the role of keratinocytes in promoting angiogenesis in mice with lineage-specific deletion of the transcription factor FOXO1. The results indicate that keratinocyte-specific deletion of Foxo1 reduces VEGFA expression in mucosal and skin wounds and leads to reduced endothelial cell proliferation, reduced angiogenesis, and impaired re-epithelialization and granulation tissue formation. In vitro FOXO1 was needed for VEGFA transcription and expression. In a porcine dermal wound-healing model that closely resembles healing in humans, local application of a FOXO1 inhibitor reduced angiogenesis. This is the first report that FOXO1 directly regulates VEGFA expression and that FOXO1 is needed for normal angiogenesis during wound healing. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Structure of the DNA deaminase domain of the HIV-1 restriction factor APOBEC3G.

The human APOBEC3G (apolipoprotein B messenger-RNA-editing enzyme, catalytic polypeptide-like 3G) protein is a single-strand DNA deaminase that inhibits the replication of human immunodeficiency virus-1 (HIV-1), other retroviruses and retrotransposons. APOBEC3G anti-viral activity is circumvented by most retroelements, such as through degradation by HIV-1 Vif. APOBEC3G is a member of a family of polynucleotide cytosine deaminases, several of which also target distinct physiological substrates. For instance, APOBEC1 edits APOB mRNA and AID deaminates antibody gene DNA. Although structures of other family members exist, none of these proteins has elicited polynucleotide cytosine deaminase or anti-viral activity. Here we report a solution structure of the human APOBEC3G catalytic domain. Five alpha-helices, including two that form the zinc-coordinating active site, are arranged over a hydrophobic platform consisting of five beta-strands. NMR DNA titration experiments, computational modelling, phylogenetic conservation and Escherichia coli-based activity assays combine to suggest a DNA-binding model in which a brim of positively charged residues positions the target cytosine for catalysis. The structure of the APOBEC3G catalytic domain will help us to understand functions of other family members and interactions that occur with pathogenic proteins such as HIV-1 Vif.

Association of CETP Taq1B and -629C > A polymorphisms with coronary artery disease and lipid levels in the multi-ethnic Singaporean population.

BACKGROUND: Hyperlipidaemia is a major risk factor for coronary artery disease (CAD) and cholesteryl ester transfer protein (CETP) gene polymorphisms are known to be associated with lipid profiles. METHODS: In this study, we investigated the association of two polymorphisms in the CETP, Taq1B (rs708272) and -629C > A (rs1800775), with CAD and lipid levels HDL-C in 662 CAD + cases and 927 controls from the Singapore population comprising Chinese, Malays and Indians. RESULTS: TaqB2 frequency was significantly lowest in the Malays (0.43) followed by Chinese (0.47) and highest in the Indians (0.56) in the controls. The B2 allele frequency was significantly lower in the Chinese CAD + cases compared to the controls (p = 0.002). The absence of the B2 allele was associated with CAD with an OR 2.0 (95% CI 1.2 to 3.4) after adjustment for the confounding effects of age, smoking, BMI, gender, hypertension, dyslipidemia and diabetes mellitus. The B2 allele was significantly associated with higher plasma HDL-C levels in the Chinese men after adjusting for confounders. Associations with plasma apoA1 levels were significant only in the Chinese men for Taq1B and -629C > A. In addition, the Taq1B polymorphism was only associated with plasma Apo B and Lp(a) in the Malay men. Significant associations were only found in non-smoking subjects with BMI <50th percentile. In this study, the LD coefficients between the Taq1B and -629C > A polymorphisms seemed to be weak. CONCLUSION: The absence the Taq1B2 allele was associated with CAD in the Chinese population only and the minor allele of the Taq1B polymorphism of the CETP gene was significantly associated with higher plasma HDL-C levels in Chinese men.

Cuproptosis-related risk score based on machine learning algorithm predicts prognosis and characterizes tumor microenvironment in head and neck squamous carcinomas.

Cuproptosis is a recently discovered type of programmed cell death that shows significant potential in the diagnosis and treatment of cancer. It has important significance in the prognosis of HSNC. This study aims to construct a cuproptosis-related prognostic model and risk score through new data analysis methods such as machine learning algorithms for the prognosis analysis of HSNC. Protein-protein interaction network and machine learning methods were employed to identify hub genes that were used to construct a TreeGradientBoosting model for predicting overall survival. The relationship between the risk scores obtained from the model and features such as tumor microenvironment (TME) and tumor immunity was explored. The C-indexes of the TreeGradientBoosting model in the training and validation cohorts were 0.776 and 0.848, respectively. The nomogram based on risk scores and clinical features showed good performance, and distinguished the TME and immunity between high-risk and low-risk groups. The cuproptosis-associated risk score can be used to predict prognoses, TME, and tumor immunity of HNSC patients.

Micro-ocean-bottom electromagnetic receiver for controlled-source electromagnetic and magnetotelluric data acquisition.

A new micro-ocean-bottom electromagnetic (EM) receiver is presented for marine magnetotelluric (MT) and controlled-source EM (CSEM) data acquisition, avoiding the bulkiness, high cost, high power consumption, and narrow bandwidth of the existing ocean-bottom EM receivers. The efficient, compact, and easy-to-use data logger employs a single 17-in. spherical glass as a float and uses an acoustic telemetry modem unit to control the burn-wire release of the seafloor instrument via a smartphone. The receiver design involves two induction coils for the magnetometer and four 8-m-span electric-field sensors for MT and CSEM data acquisition. The new ocean-bottom EM receiver was tested in sea. Compared with other miniaturized seabed EM receivers, the proposed receiver achieves better comprehensive performance for MT and CSEM data acquisition and meets the requirements of deep-mantle-structure research and seabed resource exploration.

Clinical application of a FOXO1 inhibitor improves connective tissue healing in a diabetic minipig model.

The forkhead box O1 (FOXO1) transcription factor plays a key role in wound healing process. Recently it has been reported that lineage-specific genetic ablation of FOXO1 significantly improves diabetic wound healing in a mouse model. To investigate the clinical usefulness of these findings, translational preclinical studies with a large animal model are needed. We report for the first time that the local application of a FOXO1 inhibitor (AS1842856) significantly improves connective tissue healing in a preclinical T2DM minipig model, reflected by increased collagen matrix formation, increased myofibroblast numbers, improved angiogenesis, and a shift in cell populations from pro-inflammatory (IL-1ß+, TNF-α+ and iNOS+) to pro-healing (CD163+). Our results set up the basis for the clinical application of a FOXO1 antagonist in early diabetic wounds where there is impaired connective tissue healing.

Comparison of blind surgical zone in the Henry vs. Kocher approach in the treatment of partial radial head fractures.

BACKGROUND: The Kocher approach is often adopted for surgical treatment of partial radial head fractures. However, anterior exposure of the radial head is limited by the Kocher approach. Radial head fractures are predisposed to be located at the anterior radius. The deviation of susceptible fracture locations against the regular operative approach imposes certain challenges on surgical procedures. This study explored whether there are any clinically significant differences in the exposure between the Henry and Kocher approaches. MATERIALS AND METHODS: Ten fresh-frozen cadaveric upper limbs were obtained as specimens. The radial head was exposed by both the Henry and Kocher approaches, followed by a long-axis parallel incision at the joint capsule until the capsular attachment was reached; the extracapsular ligaments and surrounding soft tissues were avoided. The 2 approaches were compared in the blind zone and in the visualized area. RESULTS: The blind-zone arc of radial head exposure with the Henry and Kocher approaches averaged 132° ± 16° and 112° ± 21°, respectively. The supinated angle between the borderline of the blind-zone arc and the biceps tuberosity-radial medullary cavity centerline averaged 268° ± 20° and 75° ± 16°, respectively. CONCLUSIONS: The Henry approach offered optimal exposure of the anterior and lateral radial head but had a blind zone at the posteromedial radial head, whereas the Kocher approach offered optimal exposure of the posterolateral radial head but had a blind zone at the anterolateral radial head. The Henry approach could be a better option for specific management of radial head fractures based on the fracture location.

Deletion of FOXO1 in chondrocytes rescues the effect of diabetes on mechanical strength in fracture healing.

Diabetes increases the risk of fracture, impairs fracture healing and causes rapid loss of the fracture callus cartilage, which was linked to increased FOXO1 expression in chondrocytes. We recently demonstrated that deletion of FOXO1 in chondrocytes blocked the premature removal of cartilage associated with endochondral bone formation during fracture healing. However, the ultimate impact of this deletion on mechanical strength was not investigated and remains unknown. Closed fractures were induced in Col2α1Cre+.FOXO1L/L mice with lineage specific deletion of FOXO1 in chondrocytes compared to littermate controls. Type 1 diabetes was induced by multiple low dose streptozotocin treatment. Thirty-five days after fracture micro CT analysis showed that diabetes significantly reduced callus volume and bone volume (P < 0.05), both which were reversed by FOXO1 deletion in chondrocytes. Diabetes significantly reduced mechanical strength measured by maximum torque, stiffness, modulus of rigidity and toughness and FOXO1 deletion in diabetic mice rescued each parameter (P < 0.05). Diabetes also reduced both bone volume and mechanical strength in non-fractured femurs. However, FOXO1 deletion did not affect bone volume or strength in non-fractured bone. These results point to the important effect that diabetes has on chondrocytes and show for the first time that the premature removal of cartilage induced by FOXO1 in chondrocytes has a significant impact on the mechanical strength of the healing bone.

Inhibitory effects of a dietary phytochemical 3,3'-diindolylmethane on the phenobarbital-induced hepatic CYP mRNA expression and CYP-catalyzed reactions in female rats.

3,3'-diindolylmethane (DIM), derived from indole-3-carbinol (I3C), is used as a dietary supplement for its putative anticancer effects that include suppression of mammary tumor growth in female rats. The mechanism of action DIM may involve its interaction(s) with hepatic cytochromes P450 (CYPs) catalyzing oxidations of 17beta-estradiol (E2). Our study showed that DIM added to hepatic microsomes of female Sprague-Dawley rats was primarily a competitive inhibitor of beta-naphthoflavone (beta-NF)- or I3C-induced CYP1A1 probe activity, and a potent mixed or uncompetitive inhibitor of phenobarbital (PB)-induced CYP2B1 or CYP2B2 probe activity, respectively. Microsomal metabolites of DIM were tentatively identified as two mono-hydroxy isomers of DIM, each formed preferentially by CYP1A1- or CYP2B1/2-catalyzed reaction. Evaluation of the effects of co-treatment of rats with PB and DIM by a full factorial ANOVA showed that DIM decreased the PB-induced CYP2B1 and CYP2B2 mRNA expression levels, and the rates of 2- and 4-hydroxylation of E2, and total E2 metabolite formation. The results suggest that interactions of DIM, and/or its mono-hydroxy metabolites, with CYP2B1 and CYP2B2 found to occur in hepatic microsomes upon addition of DIM or co-treatment of rats with DIM affect the rates of relevant oxidations of E2, and potentially protect against estrogen-dependent tumorigenesis.

Extensive mutagenesis experiments corroborate a structural model for the DNA deaminase domain of APOBEC3G.

APOBEC3G is a single-strand DNA cytosine deaminase capable of blocking retrovirus and retrotransposon replication. APOBEC3G has two conserved zinc-coordinating motifs but only one is required for catalysis. Here, deletion analyses revealed that the minimal catalytic domain consists of residues 198-384. Size exclusion assays indicated that this protein is monomeric. Many (31/69) alanine substitution derivatives of APOBEC3G198-384 retained significant to full levels of activity. These data corroborated an APOBEC2-based structural model for the catalytic domain of APOBEC3G indicating that most non-essential residues are solvent accessible and most essential residues cluster within the protein core.

Suppression of mammary gland carcinogenesis by post-initiation treatment of rats with tamoxifen or indole-3-carbinol or their combination.

This study examined whether suppression of mammary gland carcinogenesis elicited by low doses of tamoxifen (TAM) can be enhanced by concomitant treatment of rats with indole-3-carbinol (I3C), a component of cruciferous vegetables and a dietary supplement used for its putative antiestrogenicity. Two weeks after one oral dose of 7,12-dimethylbenz[a]anthracene (DMBA) at 65 mg/kg body weight, female Sprague-Dawley rats started treatment with TAM (10 microg/rat) by subcutaneous injection, I3C (250 mg/kg body weight) by oral gavage, TAM+I3C or their respective vehicles three times per week, for up to 20 weeks. Significant increases in the median latency of malignant mammary tumors and decreases in the mean tumor mass per rat were due to TAM. Significant decreases in the mean tumor number per rat in TAM, I3C and TAM+I3C-treated rats indicated a cooperative effect of the two compounds. In both DMBA-initiated and uninitiated rats, significant increases in the ratios of liver to body weight in I3C and TAM+I3C-treated groups coincided with I3C-dependent increases of hepatic cytochrome P450 levels and activities (1A1, 1A2 and 2B1/2). The ratios of uterus to body weight decreased with the number of treatments and the decreases effected by TAM were greater than those by I3C. The levels of circulating estrone were increased in response to I3C treatment and were greater in DMBA-initiated rats than in uninitiated rats, which may contribute to the preventive effect of I3C. Chemoprevention may be accomplished through up-regulation of apoptotic enzyme (caspase) activities in the mammary gland or mammary tumors. Treatment with TAM, I3C or TAM+I3C had no effect on caspase-3&7, caspase-6, caspase-8 and caspase-9 activities in the mammary tumors or mammary gland of tumor-bearing rats or that of uninitiated rats. In the mammary gland of DMBA-initiated tumor-free rats, however, I3C treatment increased the levels of caspase-3&7 and caspase-9 activities, suggesting an I3C-mediated protective effect. Even though I3C alone is a much less effective suppressing agent of mammary carcinogenesis than TAM, I3C in combination with TAM does not weaken but may foster the benefits of chemoprevention with TAM.

Structure of the complex of phosphorylated liver kinase B1 and 14-3-3ζ.

The serine/threonine protein kinase liver kinase B1 (LKB1) is a tumour suppressor and plays important roles in development and metabolism. It phosphorylates AMPK and AMPK-related kinases to regulate multiple physiological processes. Mutations in LKB1 often occur in multiple cancers. LKB1 can be suppressed by 14-3-3 proteins in a phosphorylation-dependent manner. Previously, the structure of a 14-3-3ζ-LKB1 fusion protein has been reported, revealing a phosphorylation-independent binding mode of LKB1 to 14-3-3 proteins. Here, the crystal structure of phosphorylated LKB1 peptide in complex with 14-3-3ζ was solved, which provides a structural basis for the phosphorylation-dependent recognition of LKB1 by 14-3-3 proteins.

HDAC inhibitors suppress c-Jun/Fra-1-mediated proliferation through transcriptionally downregulating MKK7 and Raf1 in neuroblastoma cells.

Activator protein 1 (AP-1) is a transcriptional factor composed of the dimeric members of bZIP proteins, which are frequently deregulated in human cancer cells. In this study, we aimed to identify an oncogenic AP-1 dimer critical for the proliferation of neuroblastoma cells and to investigate whether histone deacetylase inhibitors (HDACIs), a new generation of anticancer agents, could target the AP-1 dimer. We report here that HDACIs including trichostatin A, suberoylanilidehydroxamic acid, valproic acid and M344 can transcriptionally suppress both c-Jun and Fra-1, preceding their inhibition of cell growth. c-Jun preferentially interacting with Fra-1 as a heterodimer is responsible for AP-1 activity and critical for cell growth. Mechanistically, HDACIs suppress Fra-1 expression through transcriptionally downregulating Raf1 and subsequently decreasing MEK1/2-ERK1/2 activity. Unexpectedly, HDACI treatment caused MKK7 downregulation at both the protein and mRNA levels. Deletion analysis of the 5'-flanking sequence of the MKK7 gene revealed that a major element responsible for the downregulation by HDACI is located at -149 to -3 relative to the transcriptional start site. Knockdown of MKK7 but not MKK4 remarkably decreased JNK/c-Jun activity and proliferation, whereas ectopic MKK7-JNK1 reversed HDACI-induced c-Jun suppression. Furthermore, suppression of both MKK-7/c-Jun and Raf-1/Fra-1 activities was involved in the tumor growth inhibitory effects induced by SAHA in SH-SY5Y xenograft mice. Collectively, these findings demonstrated that c-Jun/Fra-1 dimer is critical for neuroblastoma cell growth and that HDACIs act as effective suppressors of the two oncogenes through transcriptionally downregulating MKK7 and Raf1.

Crystal structure of the DNA cytosine deaminase APOBEC3F: the catalytically active and HIV-1 Vif-binding domain.

Human APOBEC3F is an antiretroviral single-strand DNA cytosine deaminase, susceptible to degradation by the HIV-1 protein Vif. In this study the crystal structure of the HIV Vif binding, catalytically active, C-terminal domain of APOBEC3F (A3F-CTD) was determined. The A3F-CTD shares structural motifs with portions of APOBEC3G-CTD, APOBEC3C, and APOBEC2. Residues identified to be critical for Vif-dependent degradation of APOBEC3F all fit within a predominantly negatively charged contiguous region on the surface of A3F-CTD. Specific sequence motifs, previously shown to play a role in Vif susceptibility and virion encapsidation, are conserved across APOBEC3s and between APOBEC3s and HIV-1 Vif. In this structure these motifs pack against each other at intermolecular interfaces, providing potential insights both into APOBEC3 oligomerization and Vif interactions.

A Comparison of Two Single-Stranded DNA Binding Models by Mutational Analysis of APOBEC3G.

APOBEC3G is the best known of several DNA cytosine deaminases that function to inhibit the replication of parasitic genetic elements including the lentivirus HIV. Several high-resolution structures of the APOBEC3G catalytic domain have been generated, but none reveal how this enzyme binds to substrate single-stranded DNA. Here, we constructed a panel of APOBEC3G amino acid substitution mutants and performed a series of biochemical, genetic, and structural assays to distinguish between "Brim" and "Kink" models for single-strand DNA binding. Each model predicts distinct sets of interactions between surface arginines and negatively charged phosphates in the DNA backbone. Concordant with both models, changing the conserved arginine at position 313 to glutamate abolished both catalytic and restriction activities. In support of the Brim model, arginine to glutamate substitutions at positions 213, 215, and 320 also compromised these APOBEC3G activities. Arginine to glutamate substitutions at Kink model residues 374 and 376 had smaller effects. These observations were supported by A3G catalytic domain-ssDNA chemical shift perturbation experiments. The overall data set is most consistent with the Brim model for single-stranded DNA binding by APOBEC3G.

Opposing roles for E2F1 in survival and death of cerebellar granule neurons.

The transcription factor E2F1 is upregulated when cerebellar granular neurons (CGNs) undergo apoptosis under potassium deprivation. In this study, we examined the effects of E2F1 upregulation on the survival and death of CGNs isolated from C57 mice and Sprague-Dawley (SD) rats. Plasmid- and adenovirus-mediated expression of E2F1 dose-dependently induced apoptosis in mouse CGNs but unexpectedly failed to induce apoptosis in rat CGNs. Caspase 3, a marker for neuronal apoptosis, was significantly activated by ectopic E2F1 expression in mouse CGNs but not in rat CGNs. Furthermore, overexpression of E2F1 significantly promoted apoptotic progression in mouse CGNs following potassium deprivation but attenuated apoptosis in rat CGNs, whereas E2F1 lacking DNA binding ability (E2F1-M132) lost its pro-apoptotic role in mouse CGNs and anti-apoptotic role in rat CGNs. Together, our results demonstrated that upregulation of E2F1 by potassium deprivation promotes apoptosis in C57 mouse CGNs but antagonizes apoptosis in SD rat CGNs, suggesting opposing roles for E2F1 in regulating CGN fate.