pp 169-170 Clipboard
pp 171-172 Clipboard
pp 173-182 Article
The interplay between the host and Human cytomegalovirus (HCMV) plays a pivotal role in the outcome of an infection. HCMV growth in endothelial and epithelial cells requires expression of viral proteins UL128, UL130, and UL131 proteins (UL128-131), of which UL130 is the largest gene and the only one that is not interrupted by introns. Mutation of the C terminus of the UL130 protein causes reduced tropism of endothelial cells (EC). However, very few host factors have been identified that interact with the UL130 protein. In this study, HCMV UL130 protein was shown to directly interact with the human protein Snapin in human embryonic kidney HEK293 cells by Yeast two-hybrid screening, in vitro glutathione S-transferase (GST) pull-down, and co-immunoprecipitation. Additionally, heterologous expression of protein UL130 revealed co-localization with Snapin in the cell membrane and cytoplasm of HEK293 cells using fluorescence confocal microscopy. Furthermore, decreasing the level of Snapin via specific small interfering RNAs decreased the number of viral DNA copies and titer in HCMV-infected U373-S cells. Taken together, these results suggest that Snapin, the pUL130 interacting protein, has a role in modulating HCMV DNA synthesis.
pp 183-192 Article
Human cytomegalovirus-encoded miR-US4-1 promotes cell apoptosis and benefits discharge of infectious virus particles via down-regulation of glutaminyl-tRNA synthetase, QARS in HCMV-infected HELF cells
Human cytomegalovirus (HCMV) can cause congenital diseases and opportunistic infections in immunocompromised individuals. Its functional proteins and microRNAs (miRNAs) facilitate efficient viral propagation by altering host cell behaviour. Identification of functional target genes of miRNAs is an important step in studies on HCMV pathogenesis. In this study, Glutaminyl-tRNA Synthetase (QARS), which could regulate signal transduction pathways for cellular apoptosis, was identified as a direct target of hcmv-miR-US4-1. Apoptosis assay revealed that as silence of QARS by ectopic expression of hcmv-miR-US4-1 and specific small interference RNA of QARS can promote cell apoptosis in HCMV-infected HELF cells. Moreover, viral growth curve assays showed that hcmv-miR-US4-1 benefits the discharge of infectious virus particles. However, silence of hcmv-miR-US4-1 by its specific inhibitor overturned these effects. These results imply that hcmv-miR-US4-1 might have the same effects during HCMV nature infection. In general, hcmv-miR-US4-1 may involve in promoting cell apoptosis and benefiting discharge of infectious virus particles via down-regulation of QARS in HCMV-infected HELF cells.
pp 193-203 Article
A third generation promoter probe shuttle vector pKG was constructed, using the green fluorescent protein as a reporter, for in situ evaluation of Deinococcal promoter activity in Escherichia coli or Deinococcus radiodurans. The construct yielded zero background fluorescence in both the organisms, in the absence of promoter sequences. Fifteen deinococcal promoters, either harbouring Radiation and Desiccation Response Motif (RDRM) or not, were cloned in vector pKG. Only the RDRM-promoter constructs displayed (i) gamma radiation inducible GFP expression in D. radiodurans, following gamma irradiation, (ii) DdrO-mediated repression of GFP expression in heterologous E. coli, or (iii) abolition in GFP induction following gamma irradiation, in pprI mutant of D. radiodurans. Utility of pKG vector for real-time in situ assessment of deinococcal promoter function was, thus, successfully demonstrated.
pp 205-217 Article
Small-molecular-weight GTPase Rab2 has been shown to be a resident of pre-Golgi intermediates and is required for protein transport from the ER to the Golgi complex; however, Rab2 has yet to be characterized in Dictyostelium discoideum. DdRabS is a Dictyostelium Rab that is 80% homologous to DdRab1 which is required for protein transport between the ER and Golgi. Expression of GFP-tagged DdRab2 and DdRabS proteins showed localization to Golgi membranes and to the contractile vacuole system (CV) in Dictyostelium. Microscopic imaging indicates that the DdRab2 and DdRabS proteins localize at, and are essential for, the proper structure of Golgi membranes and the CV system. Dominant negative (DN) forms show fractionation of Golgi membranes, supporting their role in the structure and function of it. DdRab2 and DdRabS proteins, and their dominant negative and constitutively active (CA) forms, affect osmoregulation of the cells, possibly by the influx and discharge of fluids, which suggests a role in the function of the CV system. This is the first evidence of GTPases being localized to both Golgi membranes and the CV system in Dictyostelium.
pp 219-227 Article
Odorant receptors (OR) heterodimerizes with the OR co-receptor (Orco), forming specific odorant-gated cation channels, which are key to odor reception at the olfactory sensory neurons (OSN). Mammalian ORs are expressed in many other tissues, including testis. However, their biological implications are yet to be fully ascertained. In the mosquito, Orco is localized along the sperm tail and is indicated to maintain fidelity. Here, we show that orco expresses in Drosophila testis. The levels are higher in the somatic cyst cells. The orco-null mutants are perfectly fertile at 25°C. At 28°C, the coiled spermatid bundles are severely disrupted. The loss of Orco also disrupts the actin cap, which forms inside the head cyst cell at the rostral ends of the spermatid nuclei after coiling, and plays a key role in preventing the abnormal release of spermatids from the cyst enclosure. Both the defects are rescued by the somatic cyst cell-specific expression of the UAS-orco transgene. These results highlight a novel role of Orco in the somatic tissue during sperm release.
pp 229-236 Article
The high mobility group protein A2 (HMGA2) has been demonstrated as an architectural transcription factor that is associated with pathogenesis of many malignant cancers, however, its role in prostate cancer cells remains largely unknown. To explore whether HMGA2 participates in the development and progression of prostate cancer, small interfering RNA (siRNA) targeted on human HMGA2 was transfected to suppress the HMGA2 expression in prostate cancer PC3 and DU145 cells, and then we examined the cellular biology changes after decreased the expression of HMGA2. Our results showed that knockdown of HMGA2 markedly inhibited cell proliferation, this reduced cell proliferation was due to the promotion of cell apoptosis as the Bcl-xl was decreased, whereas Bax was up-regulated. In addition, we found that HMGA2 knockdown resulted in reduction of cell migration and invasion, as well as repressed the expression of matrix metalloproteinases (MMPs) and affected the occurrence of epithelial-mesenchymal transition (EMT) in both cell types. We further found that decreased HMGA2 expression inhibited the transforming growth factor-β (TGF-β)/Smad signaling pathway in cancer cells. In conclusion, our data indicated that HMGA2 was associated with apoptosis, migration and invasion of prostate cancer, which might be a promising therapeutic target for prostate cancer.
pp 237-249 Article
This study aims at investigating the effect of a psychogenic stress during gestation on the behaviour and haematological indices in dams as well as on the neonatal haematological status and periadolescent behaviour in their offspring. Moreover, the ability of quercetin, a natural flavonoid, to prevent the stress-induced changes was estimated. Pregnant Wistar rats were pretreated with quercetin before the exposure to a predator stress on gestational day 19. Post-stress maternal anxiety-like behaviour was assessed with a concomitant haematological analysis. In the offspring, haematological analysis and behavioural testing were performed during the postnatal stage. Our results revealed that predator stress causes an anxiety-like behaviour in dams along with a decrease in erythrocytes, a microcytosis, and a thrombocytosis. Prenatally stressed neonates manifested microcytosis and thrombocytosis with a significant polycythemia. Signs of motor hyperactivity, anxiety-like behaviour, and memory dysfunction were detected at periadolescence. Quercetin pretreatment alleviated the stress-induced behavioural and haematological impairments in dams but failed to attenuate the haematological changes in neonates. A sex-dependent effect of quercetin on behaviour was found at periadolescence. Our findings suggest that, besides a beneficial effect on haematological and behavioural anomalies in traumatized dams, quercetin may lastingly modulate the behaviour of their progeny.
pp 251-255 Article
Leptin is a protein hormone synthesized by adipocytes and is involved in the regulation of food intake and energy expenditure. We hypothesized that any change in the promoter sequence can affect the expression of the gene and hence leptin protein levels in the serum. The aim of the current study was to investigate the relationship of such a promoter variant of the leptin gene, G-2548A polymorphism, with obesity and its effect on various anthropometric and metabolic parameters in a Pakistani cohort consisting of 250 obese and 225 non-obese control subjects. Body weight, height, waist circumference (WC), hip circumference (HC) and blood pressure (BP) were measured by standard methods and levels of fasting blood glucose (FBG), total cholesterol, triglycerides, HDLC, LDLC, and leptin were determined. Genotyping was done by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The results showed that the LEP G-2548A polymorphism showed significant association with obesity in Pakistan. In addition, the polymorphism showed association with weight, height, BMI, WC, HDLC and serum leptin levels. The findings suggest that the leptin promoter G-2548A variant may play its part in the progression to obesity by not only affecting the body’s fat distribution but also by changing the serum leptin and HDLC levels.
pp 257-264 Article
Tomato (Solanum lycopersicum L.) is one of the model plants to study the carotenoid biosynthesis. In the present study, the fruit carotenoid content were quantified at different developmental stages for two contrasting genotypes viz. IIHR-249-1and IIHR-2866 by UPLC. Lycopene content was high in IIHR-249-1(19.45 mg/100g fresh weight) compared to IIHR-2866 ((1.88 mg/100g fresh weight) at the ripe stage. qPCR was performed for genes that are involved in the carotenoid biosynthetic pathway to study the difference in lycopene content in fruits of both the genotypes. The expression of Phytoene Synthase (PSY) increased by 36 fold and Phytoene desaturase (PDS) increased by 14fold from immature green stage to ripe stage in IIHR-249-1. The expression of Chloroplast lycopene β cyclase (LCY-B) and Chromoplast lycopene β cyclase (CYC-B) decreased gradually from the initial stage to the ripe stage in IIHR-249-1. IIHR 249-1 showed 3 and 1.8 fold decrease in gene expression for Chloroplast lycopene β cyclase ((LCY-B) and Chromoplast lycopene β cyclase (CYC-B) .The F2 hybrids derived from IIHR-249-1 and IIHR-2866 were analyzed at the ripe stage for lycopene content. The gene expression of Chloroplast lycopene β cyclase (LCY-B) and Chromoplast lycopene β cyclase (CYC-B) in high and low lycopene lines from F2 progenies also showed the decrease in transcript levels of both the genes in high lycopene F2 lines. We wish to suggest that the differential expression of Lycopene β -cyclases can be used in marker assisted breeding.
pp 265-275 Article
The stimulatory effect of the aqueous extract of G. lucidum, a basidiomycetes class fungus in the APE1-enzyme-mediated processing of solitary and bistranded clustered abasic sites DNA damages is presented. Abasic sites are considered the most common type of DNA damage lesions. Our study shows enhanced activity of APE1 in the processing of abasic sites in the presence of the polysaccharides fraction of G. lucidum. Remarkable increase in the amount of single-strand breaks (SSBs) and double-strand breaks (DSBs) from solitary and bistranded clustered abasic sites respectively with APE1 in the presence of the extract was found. This trend is maintained when abasic sites in DNA oligomers are exposed to fibroblast cell extracts in the presence of the extract. While DNA conformational alteration is negligible, APE1 enzyme shows characteristic changes in the alpha helix and beta strand ratio after incubation with G. lucidum extract. The enhanced reactivity of APE1 at the molecular level in the presence of G. lucidium is attributed to this effect. This study potentially amplifies the scope of the use of G. lucidum, which was earlier shown to have only reactive oxygen species (ROS) scavenging properties with regards to DNA damage inhibition.
pp 277-282 Mini-Review
Genes of the Rel/Spo homolog (RSH) superfamily synthesize and/or hydrolyse the modified nucleotides pppGpp/ppGpp (collectively referred to as (p)ppGpp) and are prevalent across diverse bacteria and in plant chloroplasts. Bacteria accumulate (p)ppGpp in response to nutrient deprivation (generically called the stringent response) and elicit appropriate adaptive responses mainly through the regulation of transcription. Although at different concentrations (p)ppGpp affect the expression of distinct set of genes, the two well-characterized responses are reduction in expression of the protein synthesis machinery and increase in the expression of genes coding for amino acid biosynthesis. In Escherichia coli, the cellular (p)ppGpp level inversely correlates with the growth rate and increasing its concentration decreases the steady state growth rate in a defined growth medium. Since change in growth rate must be accompanied by changes in cell cycle parameters set through the activities of the DNA replication and cell division apparatus, (p)ppGpp could coordinate protein synthesis (cell mass increase) with these processes. Here we review the role of (p)ppGpp in bacterial cell cycle regulation.
pp 283-294 Review
Sex determination in most insects is structured as a gene cascade, wherein a primary signal is passed through a series of sex-determining genes, culminating in a downstream double-switch known as doublesex that decides the sexual fate of the embryo. From the literature available on sex determination cascades, it becomes apparent that sex determination mechanisms have evolved rapidly. The primary signal that provides the cue to determine the sex of the embryo varies remarkably, not only among taxa, but also within taxa. Furthermore, the upstream key gene in the cascade also varies between species and even among closely related species. The order Insecta alone provides examples of astoundingly complex diversity of upstream key genes in sex determination mechanisms. Besides, unlike key upstream genes, the downstream double-switch gene is alternatively spliced to form functional sex-specific isoforms. This sex-specific splicing is conserved across insect taxa. The genes involved in the sex determination cascade such as Sex-lethal (Sxl) in Drosophila melanogaster, transformer (tra) in many other dipterans, coleopterans and hymenopterans, Feminizer (fem) in Apis mellifera, and IGF-II mRNA-binding protein (Bmimp) in Bombyx mori are reported to be regulated by an autoregulatory positive feedback loop. In this review, by taking examples from various insects, we propose the hypothesis that autoregulatory loop mechanisms of sex determination might be a general strategy. We also discuss the possible reasons for the evolution of autoregulatory loops in sex determination cascades and their impact on binary developmental choices.
pp 295-311 Review
The bromodomains and extra-terminal domain (BET) family proteins recognize acetylated chromatin through their bromodomains (BDs) and helps in regulating gene expression. BDs are chromatin ‘readers’; by interacting with acetylated lysines on the histone tails, they recruit chromatin-regulating proteins on the promoter region to regulate gene expression and repression. Extensive efforts have been employed by the scientific communities worldwide, to identify and develop potential inhibitors of BET family BDs to regulate protein expression by inhibiting acetylated histone (H3/H4) interactions. Several small molecule inhibitors have been reported, which not only have high affinity, but also have high specificity to BET BDs. These developments make BET family proteins to be an important therapeutic targets, for major diseases such as cancer, neurological disorders, obesity and inflammation. Here, we review and discuss the structural biology of BET family BDs and their applications in major diseases.
pp 313-324 Review
Breast cancer resistance protein (BCRP, ABCP or MXR) / ATP-binding cassette subfamily G member 2 (ABCG2) was characterized as a multidrug resistance efflux transporter in 1998. ABCG2 physiologically acts as a part of a self-defense mechanism for the organism; it enhances eliminating of toxic xenobiotic substances and harmful agents in the intestine, as well as through the blood-brain barrier and placental. ABCG2 recognizes and transports numerous anticancer drugs including conventional chemotherapeutic and new targeted small therapeutic molecules in clinical usage. Development of ABCG2 inhibitors for clinical usage may allow increased penetration of therapeutic agents into sanctuary sites and increased their intestinal absorption. In this report, we review the mechanisms that modulate MDR mediated by the ABC transporter ABCG2 in normal and cancer cells by different levels including, epigenetic modifications, transcriptional, posttranscriptional, translation and posttranslational regulation. Some clinical applications of ABCG2 inhibitors, also is explained.
Volume 42 | Issue 4