Correction to the pathogenic alternative splicing, caused by the common GNB3 c.825C>T allele, using a novel, antisense morpholino

The very common GNB3 c.825C>T polymorphism (rs5443), is present in approximately half of all human chromosomes. Significantly the presence of the GNB3 825T allele has been strongly associated, with predisposition to essential hypertension. Paradoxically the presence of the GNB3 825T allele, in exon 10, introduces a pathogenic alternative RNA splice site into the middle of exon 9. To attempt to correct this pathogenic aberrant splicing, we therefore bioinformatically designed, using a Gene Tools® algorithm, a GNB3 specific, antisense morpholino. It was hoped that this morpholino would behave in vitro as either a potential “ splice blocker and/or exon skipper, to both bind and inhibit/reduce the aberrant splicing of the GNB3, 825T allele. On transfecting a human lymphoblast cell line homozygous for the 825T allele, with this antisense morpholino, we encouragingly observed both a significant reduction (from ~58% to ~5%) in the production of the aberrant smaller GNB3 transcript, and a subsequent increase in the normal GNB3 transcript (from ~42% to ~95%). Our results demonstrate the potential use of a GNB3 specific antisense morpholino, as a pharmacogenetic therapy for essential hypertension

Mutation in the guanine nucleotide-binding protein beta-3 causes retinal degeneration and embryonic mortality in chickens

PURPOSE. To identify the gene defect that causes blindness and the predisposition to embryonic death in the retinopathy globe enlarged (rge) chicken. METHODS. Linkage analysis, with previously uncharacterized microsatellite markers from chicken chromosome 1, was performed on 138 progeny of an rge/+ and an rge/rge cross, and candidate genes were sequenced. RESULTS. The rge locus was refined and the gene for guanine nucleotide-binding protein β-3 (GNB3), which encodes a cone transducin β subunit, was found to have a 3-bp deletion (D153del) that segregated with the rge phenotype. This mutation deleted a highly conserved aspartic acid residue in the third of seven WD domains in GNB3. In silico modeling suggested that this mutation destabilized the protein. Furthermore, a 70% reduction was found in immunoreactivity to anti-GNB3 in the rge-affected retina. CONCLUSIONS. These findings implicate the β-subunit of cone transducin as the defective protein underlying the rge phenotype. Furthermore, GNB3 is ubiquitously expressed, and the c.825C→T GNB3 splicing variant (MIM 139130) has been associated with hypertension, obesity, diabetes, low birth weight, coronary heart disease, and stroke in the human population. It therefore seems likely that the defect underlying these human diseases also causes reduced embryonic viability in the rge chicken, making it a powerful model for studying the pathology involved in these associations

The alternate GNB3 splice variant, Gβ3s, exhibits an altered signalling response to EGF stimulation, which leads to enhanced cell migration

It has recently been reported that the duplication of the GNB3 gene has been shown to be directly linked to an obesity phenotype, both in humans and also in a humanised mouse model. Moreover, the common human GNB3 c.825C>T polymorphism (rs5443) causes this ubiquitously expressed gene to be aberrantly spliced approximately 50% of the time leading to the production of both a normal Gβ3 protein and a truncated, possibly less stable subunit, known as Gβ3s. The presence of the GNB3 825T allele has previously been shown to be associated with predisposition to hypertension, obesity, various cancers, Alzheimers, age related cognitive function, erectile dysfunction as well as a marker for pharmacogenetic drug action. Great controversy, however, currently exists as to whether these phenotypes associated with the 825T allele are a) mainly due to the presence of the smaller, possibly more active, Gβ3s subunit or b) merely down to the haploinsufficiency of the normal GNB3 transcript, due to its frequent aberrant splicing. In order to try and address these two conflicting hypothesis, we report on the identification and characterisation of signalling alterations unique to the presence of Gβ3s protein subunit. Moreover we also show the physiological consequences associated with altered signalling, directly induced by the Gβ3s subunit. For this, we used both an EBV transformed lymphoblast cell line homozygote for GNB3 825T/825T (TT) and a stable Gβ3s expressing recombinant COS-7 clone. In both of these cell lines that express the Gβ3s subunit, we found enhanced cytosolic calcium influx upon stimulation with EGF, TGFα and VEGF ligands, as compared to “normal” GNB3 controls with the 825C/825C (CC) genotype. This aberrant calcium influx also led to an increase in ERK, but not AKT1, phosphorylation. Despite the lack of AKT1 activation, we paradoxically observed a significant increase in phosphorylation of its downstream substrates, namely mTOR and p70S6k (KS6B2). Moreover we observed a decrease in phospho FoxO3a only in Gβ3s expressing cells, but not in the “normal” GNB3 (CC) control cell line. The presence of the Gβ3s subunit also appeared to alter the distinct localisation patterns of both Foxo3a and AKT1, while also increasing the colocalisation of mTOR and p70S6K. Subsequent growth factor stimulation studies revealed that EGF treatment, of Gβ3s expressing cells, appeared to cause a significant decrease in cAMP levels, which, in turn resulted in both enhanced caveolin-1a phosphorylation, and an increase in actin stress fibre formation. The identification of these distinct Gβ3s specific signalling alterations were indicative of a more aggressive migratory phenotype. This led us to further investigate and confirm that the presence of the Gβ3s subunit also appears to cause significantly enhanced migration and robust scratch wound healing kinetics, as compared to cells harbouring only the normal copy of the gene. These data therefore present convincing evidence that the Gβ3s subunit is stable, functional and its presence can significantly alter signalling pathways, in different cell types

The D153del mutation in GNB3 gene causes tissue specific signalling patterns and an abnormal renal morphology in rge chickens

Background The GNB3 gene is expressed in cone but not rod photoreceptors of vertebrates, where it acts as the β transducin subunit in the colour visual transduction process. A naturally occurring mutation ‘D153del’ in the GNB3 gene causes the recessively inherited blinding phenotype retinopathy globe enlarged (rge) disease in chickens. GNB3 is however also expressed in most other vertebrate tissues suggesting that the D153del mutation may exert pathological effects that outlie from eye. Principal Findings Recombinant studies in COS-7 cells that were transfected with normal and mutant recombinant GNB3 constructs and subjected to cycloheximide chase showed that the mutant GNB3d protein had a much shorter half life compared to normal GNB3. GNB3 codes for the Gβ3 protein subunit that, together with different Gγ and Gα subunits, activates and regulates phosphorylation cascades in different tissues. As expected, the relative levels of cGMP and cAMP secondary messengers and their activated kinases such as MAPK, AKT and GRK2 were also found to be altered significantly in a tissue specific manner in rge chickens. Histochemical analysis on kidney tissue sections, from rge homozygous affected chickens, showed the chickens had enlargement of the glomerular capsule, causing glomerulomegaly and tubulointerstitial inflammation whereas other tissues (brain, heart, liver, pancreas) were unaffected. Significance These findings confirm that the D153del mutation in GNB3 gene targets GNB3 protein to early degradation. Lack of GNB3 signalling causes reduced phosphorylation activity of ERK2 and AKT leading to severe pathological phenotypes such as blindness and renal abnormalities in rge chickens

Homozygous in-frame deletion in CATSPERE in a man producing spermatozoa with loss of CatSper function and compromised fertilizing capacity

STUDY QUESTIONDoes a man (patient 1) with a previously described deficiency in principle cation channel of sperm (CatSper) function have a mutation in the CatSper-epsilon (CATSPERE) and/or CatSper-zeta (CATSPERZ) gene?SUMMARY ANSWERPatient 1 has a homozygous in-frame 6-bp deletion in exon 18 (c.2393_2398delCTATGG, rs761237686) of CATSPERE.WHAT IS KNOWN ALREADYCatSper is the principal calcium channel of mammalian spermatozoa. Spermatozoa from patient 1 had a specific loss of CatSper function and were unable to fertilize at IVF. Loss of CatSper function could not be attributed to genetic abnormalities in coding regions of seven CatSper subunits. Two additional subunits (CatSper-epsilon (CATPSERE) and CatSper-zeta (CATSPERZ)) were recently identified, and are now proposed to contribute to the formation of the mature channel complex.STUDY DESIGN, SIZE, DURATIONThis was a basic medical research study analysing genomic data from a single patient (patient 1) for defects in CATSPERE and CATSPERZ.PARTICIPANTS/MATERIALS, SETTING, METHODSThe original exome sequencing data for patient 1 were analysed for mutations in CATSPERE and CATSPERZ. Sanger sequencing was conducted to confirm the presence of a rare variant.MAIN RESULTS AND THE ROLE OF CHANCEPatient 1 is homozygous for an in-frame 6-bp deletion in exon 18 (c.2393_2398delCTATGG, rs761237686) of CATSPERE that is predicted to be highly deleterious.LIMITATIONS, REASONS FOR CAUTIONThe nature of the molecular deficit caused by the rs761237686 variant and whether it is exclusively responsible for the loss of CatSper function remain to be elucidated.WIDER IMPLICATIONS OF THE FINDINGSPopulation genetics are available for a significant number of predicted deleterious variants of CatSper subunits. The consequence of homozygous and compound heterozygous forms on sperm fertilization potential could be significant. Selective targeting of CatSper subunit expression maybe a feasible strategy for the development of novel contraceptives.STUDY FUNDING/COMPETING INTEREST(S)This study was funded by project grants from the MRC (MR/K013343/1 and MR/012492/1), Chief Scientist Office/NHS research Scotland. This work was also supported by NIH R01GM111802, Pew Biomedical Scholars Award 00028642 and Packer Wentz Endowment Will to P.V.L. C.L.R.B is the editor-in-chief of Molecular Human Reproduction, has received lecturing fees from Merck and Ferring, and is on the Scientific Advisory Panel for Ohana BioSciences. C.L.R.B was chair of the World Health Organization Expert Synthesis Group on Diagnosis of Male infertility (2012–2016)

New measurement paradigms

This collection of New Measurement Paradigms papers represents a snapshot of the variety of measurement methods in use at the time of writing across several projects funded by the National Science Foundation (US) through its REESE and DR K–12 programs. All of the projects are developing and testing intelligent learning environments that seek to carefully measure and promote student learning, and the purpose of this collection of papers is to describe and illustrate the use of several measurement methods employed to achieve this. The papers are deliberately short because they are designed to introduce the methods in use and not to be a textbook chapter on each method. The New Measurement Paradigms collection is designed to serve as a reference point for researchers who are working in projects that are creating e-learning environments in which there is a need to make judgments about students’ levels of knowledge and skills, or for those interested in this but who have not yet delved into these methods

Visual Orbits of Spectroscopic Binaries with the CHARA Array. III. HD 8374 and HD 24546

We present the visual orbits of two long period spectroscopic binary stars, HD 8374 and HD 24546, using interferometric observations acquired with the CHARA Array and the Palomar Testbed Interferometer. We also obtained new radial velocities from echelle spectra using the APO 3.5 m and Fairborn 2.0 m telescopes. By combining the visual and spectroscopic observations, we solve for the full, three-dimensional orbits and determine the stellar masses and distances to within 3% uncertainty. We then estimate the effective temperature and radius of each component star through Doppler tomography and spectral energy distribution analyses, in order to compare the observed stellar parameters to the predictions of stellar evolution models. For HD 8374, we find masses of M1 = 1.636 +/- 0.050 Msun and M2 = 1.587 +/- 0.049 Msun, radii of R1 = 1.84 +/- 0.05 Rsun and R2 = 1.66 +/- 0.12 Rsun, temperatures of Teff1 = 7280 +/- 110 K and Teff2 = 7280 +/- 120 K, and an estimated age of 1.0 Gyr. For HD 24546, we find masses of M1 = 1.434 +/- 0.014 Msun and M2 = 1.409 +/- 0.014 Msun, radii of R1 = 1.67 +/- 0.06 Rsun and R2 = 1.60 +/- 0.10 Rsun, temperatures of Teff1 = 6790 +/- 120 K and Teff2 = 6770 +/- 90 K, and an estimated age of 1.4 Gyr. HD 24546 is therefore too old to be a member of the Hyades cluster, despite its physical proximity to the group.Comment: 18 pages, 10 figures. Accepted for publication in A

ABCB1 (MDR1) polymorphisms and ovarian cancer progression and survival: A comprehensive analysis from the Ovarian Cancer Association Consortium and The Cancer Genome Atlas

<b>Objective</b> <i>ABCB1</i> encodes the multi-drug efflux pump P-glycoprotein (P-gp) and has been implicated in multi-drug resistance. We comprehensively evaluated this gene and flanking regions for an association with clinical outcome in epithelial ovarian cancer (EOC).<p></p> <b>Methods</b> The best candidates from fine-mapping analysis of 21 <i>ABCB1</i> SNPs tagging C1236T (rs1128503), G2677T/A (rs2032582), and C3435T (rs1045642) were analysed in 4616 European invasive EOC patients from thirteen Ovarian Cancer Association Consortium (OCAC) studies and The Cancer Genome Atlas (TCGA). Additionally we analysed 1,562 imputed SNPs around ABCB1 in patients receiving cytoreductive surgery and either ‘standard’ first-line paclitaxel–carboplatin chemotherapy (n = 1158) or any first-line chemotherapy regimen (n = 2867). We also evaluated ABCB1 expression in primary tumours from 143 EOC patients.<p></p> <b>Result</b> Fine-mapping revealed that rs1128503, rs2032582, and rs1045642 were the best candidates in optimally debulked patients. However, we observed no significant association between any SNP and either progression-free survival or overall survival in analysis of data from 14 studies. There was a marginal association between rs1128503 and overall survival in patients with nil residual disease (HR 0.88, 95% CI 0.77–1.01; p = 0.07). In contrast, <i>ABCB1</i> expression in the primary tumour may confer worse prognosis in patients with sub-optimally debulked tumours.<p></p> <b>Conclusion</b> Our study represents the largest analysis of <i>ABCB1</i> SNPs and EOC progression and survival to date, but has not identified additional signals, or validated reported associations with progression-free survival for rs1128503, rs2032582, and rs1045642. However, we cannot rule out the possibility of a subtle effect of rs1128503, or other SNPs linked to it, on overall survival.<p></p&gt