Mutation in the Cadherin Gene Is a Key Factor for Pink Bollworm Resistance to Bt Cotton in China

Transgenic crops producing Bacillus thuringiensis (Bt) toxins are widely planted for insect control, but their efficacy may decrease as insects evolve resistance. Understanding the genetic basis of insect resistance is essential for developing an integrated strategy of resistance management. To understand the genetic basis of resistance in pink bollworm (Pectinophora gossypiella) to Bt cotton in the Yangtze River Valley of China, we conducted an F2 screening for alleles associated with resistance to the Bt (Cry1Ac) protein for the first time. A total of 145 valid single-paired lines were screened, among which seven lines were found to carry resistance alleles. All field parents in those seven lines carried recessive resistance alleles at the cadherin locus, including three known alleles, r1, r13 and r15, and two novel alleles, r19 and r20. The overall frequency of resistance alleles in 145 lines was 0.0241 (95% CI: 0.0106–0.0512). These results demonstrated that resistance was rare and that recessive mutation in the cadherin gene was the primary mechanism of pink bollworm resistance to Bt cotton in the Yangtze River Valley of China, which will provide a scientific basis for implementing targeted resistance management statics of pink bollworm in this region.

Prenatal and Postnatal Manifestations of Congenital Chloride Diarrhea Due to a Heterozygote Variant of the SLC26A3 Gene: A Case Report

Congenital chloride diarrhea (CCD) is caused by a recessive mutation in the SLC26A3 gene and characterized mainly by watery diarrhea, hypochloremia and metabolic alkalosis. Various different mutations in SLC26A3 are responsible for the disease. In the prenatal period, the symptoms of CCD may include polyhydramnios, preterm labor and abdominal distension. The main feature of CCD is chloride-rich diarrhea, which leads to excessive loss of fluid and salt immediately after birth and is followed by weight loss and dehydration. Hyponatremia and hypochloremia are soon accompanied by hypokalemia and metabolic alkalosis. Untreated CCD is fatal even in the first weeks of life. Diagnosis is made by high fecal chloride concentrations in patients with serum electrolytes corrected by salt substitution and confirmed using genetic testing of peripheral blood samples. Here, we detail prenatal and postnatal manifestations of a preterm infant, born via Caesarian section, who was suspected to suffer intrauterine bowel obstruction. Upper median laparotomy was performed and no intestinal abnormalities found. The course of the neonatal period was complicated by severe diarrhea with hypochloremia, hyponatremia and metabolic alkalosis. Based on the patient's clinical picture and stool examination, a diagnosis of CCD was established. Mutation of the SLC26A3 gene was confirmed using genetic testing.

Vocal cord paralysis as a presenting sign of autosomal recessive spinocerebellar atrophy type 10

Acquired vocal cord paralysis (VCP) is caused by dysfunction or injury of one or both recurrent laryngeal nerves. Here we report a 41-year-old man with spinocerebellar atrophy, autosomal recessive type 10 (SCAR10) due to an autosomal recessive mutation in the ANO10 gene, with VCP as the presenting symptom. He later developed ataxia and speech disturbance.

Sensory transduction is required for normal development and maturation ofcochlear inner hair cell synapses

Acoustic overexposure and aging can damage auditory synapses in the inner ear by a process known as synaptopathy. These insults may also damage hair bundles and the sensory transduction apparatus in auditory hair cells. However, a connection between sensory transduction and synaptopathy has not been established. To evaluate potential contributions of sensory transduction to synapse formation and development, we assessed inner hair cell synapses in several genetic models of dysfunctional sensory transduction, including mice lacking Transmembrane Channel-like (Tmc) 1, Tmc2 or both, in Beethoven mice which carry a dominant Tmc1 mutation and in Spinner mice which carry a recessive mutation in Transmembrane inner ear (Tmie). Our analyses reveal loss of synapses in the absence of sensory transduction and preservation of synapses in Tmc1-null mice following restoration of sensory transduction via Tmc1 gene therapy. These results provide insight into the requirement of sensory transduction for hair cell synapse development and maturation.

Reviewing the consequences of genetic purging on the success of rescue programs

Genetic rescue is increasingly considered a promising and underused conservation strategy to reduce inbreeding depression and restore genetic diversity in endangered populations, but the empirical evidence supporting its application is limited to a few generations. Here we discuss on the light of theory the role of inbreeding depression arising from partially recessive deleterious mutations and of genetic purging as main determinants of the medium to long-term success of rescue programs. This role depends on two main predictions: (1) The inbreeding load hidden in populations with a long stable demography increases with the effective population size; and (2) After a population shrinks, purging tends to remove its (partially) recessive deleterious alleles, a process that is slower but more efficient for large populations than for small ones. We also carry out computer simulations to investigate the impact of genetic purging on the medium to long term success of genetic rescue programs. For some scenarios, it is found that hybrid vigor followed by purging will lead to sustained successful rescue. However, there may be specific situations where the recipient population is so small that it cannot purge the inbreeding load introduced by migrants, which would lead to increased fitness inbreeding depression and extinction risk in the medium to long term. In such cases, the risk is expected to be higher if migrants came from a large non-purged population with high inbreeding load, particularly after the accumulation of the stochastic effects ascribed to repeated occasional migration events. Therefore, under the specific deleterious recessive mutation model considered, we conclude that additional caution should be taken in rescue programs. Unless the endangered population harbors some distinctive genetic singularity whose conservation is a main concern, restoration by continuous stable gene flow should be considered, whenever feasible, as it reduces the extinction risk compared to repeated occasional migration and can also allow recolonization events.

“Recurrent Papillary Necrosis and Nephrocalcinosis Induced by Nonsteroidal Anti-Inflammatory Drugs for Gouty Arthritis Associated with Congenital Chloride-Losing Diarrhea: A Major Risk for Kidney Loss”

Congenital chloride-losing diarrhea (CCLD) is a rare genetic disorder due to autosomal recessive mutation in the SLC26A3 gene on chromosome 7. It is characterized with chronic watery diarrhea with high fecal chloride (Cl: >90 mmol/L), low potassium (K), and metabolic alkalosis with low urinary Cl and K. The overall long-term prognosis is favorable with optimal life-long salt and K supplementation. In this case report, we describe a man with progressive renal failure and small kidneys that showed nephrocalcinosis and papillary necrosis. His disease was diagnosed since birth and was confirmed by our tests. He was incompliant with therapy and had developed gout. The latter complication of his disease has led to excessive NSAID use over the past years. Reinstitution of diet, drug therapy, and allopurinol had stabilized his renal disease for 1 year of follow-up. In conclusion, excessive analgesic use is a risk factor for renal failure in CCLD.

ATP-citrate lyase promotes axonal transport across species

Microtubule (MT)-based transport is an evolutionary conserved process finely tuned by posttranslational modifications. Among them, α-tubulin acetylation, primarily catalyzed by a vesicular pool of α-tubulin N-acetyltransferase 1 (Atat1), promotes the recruitment and processivity of molecular motors along MT tracks. However, the mechanism that controls Atat1 activity remains poorly understood. Here, we show that ATP-citrate lyase (Acly) is enriched in vesicles and provide Acetyl-Coenzyme-A (Acetyl-CoA) to Atat1. In addition, we showed that Acly expression is reduced upon loss of Elongator activity, further connecting Elongator to Atat1 in a pathway regulating α-tubulin acetylation and MT-dependent transport in projection neurons, across species. Remarkably, comparable defects occur in fibroblasts from Familial Dysautonomia (FD) patients bearing an autosomal recessive mutation in the gene coding for the Elongator subunit ELP1. Our data may thus shine light on the pathophysiological mechanisms underlying FD.

Nonsense-associated alternative splicing as a putative reno-protective mechanism in Pkhd1cyli/Pkhd1cyli mutant mice

Autosomal recessive polycystic kidney disease (ARPKD) is a hereditary hepato-renal fibrocystic disorder and a significant genetic cause of childhood morbidity and mortality. Mutations in the Polycystic Kidney and Hepatic Disease 1 (PKHD1) gene cause all typical forms of ARPKD. Several mouse strains carrying diverse genetically engineered disruptions in the orthologous Pkhd1 gene have been generated. The current study describes a novel spontaneous mouse recessive mutation causing a cystic liver phenotype resembling the hepato-biliary disease characteristic of human ARPKD. Here we describe mapping of the cystic liver mutation to the Pkhd1 interval on Chromosome 1 and identification of a frameshift mutation within Pkhd1 exon 48 predicted to result in premature translation termination. Mice homozygous for the new mutation, symbollzed Pkhd1cyli, lack renal pathology, consistent with previously generated Pkhd1 mouse mutants that fail to recapitulate human kidney disease. We have identified a profile of alternatively spliced Pkhd1 renal transcripts that are distinct in normal versus mutant mice. The Pkhd1 transcript profile in mutant kidneys is consistent with predicted outcomes of nonsense-associated alternative splicing (NAS) and nonsense mediated decay (NMD). Overall levels of Pkhd1 transcripts in mutant mouse kidneys were reduced compared to kidneys of normal mice, and Pkhd1 encoded protein in mutant kidneys was undetectable by immunoblotting. We suggest that in Pkhd1cyli/Pkhd1cyli (cyli) mice, mutation-promoted Pkhd1 alternative splicing in the kidney yields transcripts encoding low-abundance protein isoforms lacking exon 48 encoded amino acid sequences that are sufficiently functional so as to attenuate expression of a renal cystic disease phenotype.

Bilateral Helicoid Peri-papillary Sub-retinal Fibrosis Due to a Biallelic NR2E3 Mutation: Describing Variable Expressivity of a Single Genetic Mutation

Background: To describe different clinical presentations of NR2E3 (nuclear receptor subfamily 2, group E, member 3; OMIM 604485) recessive mutation in two families and within one family. Design: Interventional family study. Results: Our first case was a one-year-old male child with high hyperopia and refractive accommodative esotropia. In retinal examination, peri-papillary sub-retinal fibrosis with a helicoid configuration was observed in both eyes. Parents and the only sibling had no pathologic finding in the eyes. The child showed to have severely reduced responses in both photopic and scotopic electroretinogram components. In genetic investigation, a homozygous autosomal recessive mutation in NR2E3 gene was discovered in the affected child, while the other family members were heterozygous for this mutation. We followed up the patient for 3 years and no new lesion developed during this time period. The second case was a 13-year-old male child who was referred to retina clinic for decreased vision in the right eye. In retina examination, there were nummular pigmentary changes at the level of retinal pigment epithelium and along the vascular arcades with foveo-schitic changes in both eyes. A choroidal neovascularization (CNV) was noticed in macula of his right eye. Genetic evaluation proved the same mutation in NR2E3 gene. Family history was remarkable for an uncle, an aunt and two cousins with night blindness. In retina examination, asymptomatic father of proband showed to have slight pallor of optic nerve head and arterial narrowing in both eyes. Conclusion: NR2E3 gene mutation can cause heterogeneous clinical manifestations such as slight retinal changes in the absence of any visual symptoms to high hyperopia associated with helicoid peri-papillary sub-retinal fibrosis.

The Efficacy of Naïve versus Modified Mesenchymal Stem Cells in Improving Muscle Function in Duchenne Muscular Dystrophy: A Systematic Review

As one of the most common genetic conditions, Duchenne muscular dystrophy (DMD) is a fatal disease caused by a recessive mutation resulting in muscle weakness in both voluntary and involuntary muscles and, eventually, in death because of cardiovascular failure. Currently, there is no pharmacologically curative treatment of DMD, but there is evidence supporting that mesenchymal stem cells (MSCs) are a novel solution for treating DMD. This systematic review focused on elucidating the therapeutic efficacy of MSCs on the DMD in vivo model. A key issue of previous studies was the material-choice, naïve MSCs or modified MSCs; modified MSCs are activated by culture methods or genetic modification. In summary, MSCs seem to improve pulmonary and cardiac functions and thereby improve survival regardless of them being naïve or modified. The improved function of distal skeletal muscles was observed only with primed MSCs treatment but not naïve MSCs. While MSCs can provide significant benefits to DMD mouse models, there is little to no data on the results in human patients. Due to the limited number of human studies, the differences in study design, and the insufficient understanding of mechanisms of action, more rigorous comparative trials are needed to elucidate which types of MSCs and modifications have optimal therapeutic potential.