Proximal Deletion Research Articles

Dynamin-Related Protein 1 Deficiency Promotes Recovery from AKI.

The proximal tubule epithelium relies on mitochondrial function for energy, rendering the kidney highly susceptible to ischemic AKI. Dynamin-related protein 1 (DRP1), a mediator of mitochondrial fission, regulates mitochondrial function; however, the cell-specific and temporal role of DRP1 in AKI in vivo is unknown. Using genetic murine models, we found that proximal tubule-specific deletion of Drp1 prevented the renal ischemia-reperfusion-induced kidney injury, inflammation, and programmed cell death observed in wild-type mice and promoted epithelial recovery, which associated with activation of the renoprotective β-hydroxybutyrate signaling pathway. Loss of DRP1 preserved mitochondrial structure and reduced oxidative stress in injured kidneys. Lastly, proximal tubule deletion of DRP1 after ischemia-reperfusion injury attenuated progressive kidney injury and fibrosis. These results implicate DRP1 and mitochondrial dynamics as an important mediator of AKI and progression to fibrosis and suggest that DRP1 may serve as a therapeutic target for AKI.

Molecular and clinical delineation of 2p15p16.1 microdeletion syndrome.

Interstitial 2p15p16.1 microdeletion is a rare chromosomal syndrome previously reported in 33 patients. It is characterized by intellectual disability, developmental delay, autism spectrum disorders, microcephaly, short stature, dysmorphic features, and multiple congenital organ defects. It is defined as a contiguous gene syndrome and two critical regions have been proposed at 2p15 and 2p16.1 loci. Nevertheless, patients with deletion of both critical regions shared similar features of the phenotype and the correlation genotype-phenotype is still unclear. We review all published cases and describe three additional patients, to define the phenotype-genotype correlation more precisely. We reported on two patients including the first prenatal case described so far, carrying a 2p15 deletion affecting two genes: XPO1 and part of USP34. Both patients shared similar features including facial dysmorphism and cerebral abnormalities. We considered the genes involved in the deleted segment to further understand the abnormal phenotype. The third case we described here was a 4-year-old boy with a heterozygous de novo 427 kb deletion encompassing BCL11A and PAPOLG at 2p16.1. He displayed speech delay, autistic traits, and motor stereotypies associated with brain structure abnormalities. We discuss the contribution of the genes included in the deletion to the abnormal phenotype. Our three new patients compared to previous cases, highlighted that despite two critical regions, both distal deletion at 2p16.1 and proximal deletion at 2p15 are associated with phenotypes that are very close to each other. Finally, we also discuss the genetic counseling of this microdeletion syndrome particularly in the course of prenatal diagnosis.

Differential action of glucocorticoids on apolipoprotein E gene expression in macrophages and hepatocytes.

Apolipoprotein E (apoE) has anti-atherosclerotic properties, being involved in the transport and clearance of cholesterol-rich lipoproteins as well as in cholesterol efflux from cells. We hypothesized that glucocorticoids may exert anti-inflammatory properties by increasing the level of macrophage-derived apoE. Our data showed that glucocorticoids increased apoE expression in macrophages in vitro as well as in vivo. Dexamethasone increased ~6 fold apoE mRNA levels in cultured peritoneal macrophages and RAW 264.7 cells. Administered to C57BL/6J mice, dexamethasone induced a two-fold increase in apoE expression in peritoneal macrophages. By contrast, glucocorticoids did not influence apoE expression in hepatocytes, in vitro and in vivo. Moreover, dexamethasone enhanced apoE promoter transcriptional activity in RAW 264.7 macrophages, but not in HepG2 cells, as tested by transient transfections. Analysis of apoE proximal promoter deletion mutants, complemented by protein-DNA interaction assays demonstrated the functionality of a putative glucocorticoid receptors (GR) binding site predicted by in silico analysis in the -111/-104 region of the human apoE promoter. In hepatocytes, GR can bind to their specific site within apoE promoter but are not able to modulate the gene expression. The modulatory blockade in hepatocytes is a consequence of partial involvement of transcription factors and other signaling molecules activated through MEK1/2 and PLA2/PLC pathways. In conclusion, our study indicates that glucocorticoids (1) differentially target apoE gene expression; (2) induce a significant increase in apoE level specifically in macrophages. The local increase of apoE gene expression in macrophages at the level of the atheromatous plaque may have therapeutic implications in atherosclerosis.

Proximal tubule glutamine synthetase expression is necessary for the normal response to dietary protein restriction.

Dietary protein restriction has multiple benefits in kidney disease. Because protein intake is a major determinant of endogenous acid production, it is important that net acid excretion changes in parallel during changes in dietary protein intake. Dietary protein restriction decreases endogenous acid production and decreases urinary ammonia excretion, a major component of net acid excretion. Glutamine synthetase (GS) catalyzes the reaction of [Formula: see text] and glutamate, which regenerates the essential amino acid glutamine and decreases net ammonia generation. Because renal proximal tubule GS expression increases during dietary protein restriction, this could contribute to the decreased ammonia excretion. The purpose of the current study was to determine the role of proximal tubule GS in the renal response to protein restriction. We generated mice with proximal tubule-specific GS deletion (PT-GS-KO) using Cre-loxP techniques. Cre-negative (Control) and PT-GS-KO mice in metabolic cages were provided 20% protein diet for 2 days and were then changed to low-protein (6%) diet for the next 7 days. Additional PT-GS-KO mice were maintained on 20% protein diet. Dietary protein restriction caused a rapid decrease in urinary ammonia excretion in both genotypes, but PT-GS-KO blunted this adaptive response significantly. This occurred despite no significant genotype-dependent differences in urinary pH or in serum electrolytes. There were no significant differences between Control and PT-GS-KO mice in expression of multiple other proteins involved in renal ammonia handling. We conclude that proximal tubule GS expression is necessary for the appropriate decrease in ammonia excretion during dietary protein restriction.

A Rare Chromosomal Disorder – 14q Interstitial Deletion Syndrome

Abstract Introduction: Interstitial deletions of the long arm of chromosome 14q (OMIM 613457) are very rare conditions. Case presentation: We present a 3-month-old male patient with dysmorphic features and congenital heart defect associated with a small interstitial deletion of chromosome 14q, identified by cytogenetic analysis as 46,XY,del(14)(q11q12). Dysmorphic features included microcephaly, broad nasal bridge, micrognathia, large and poorly folded auricular lobes and long digits. He also present rectus abdominis diastasis and umbilical hernia. The cranial computer tomography showed partial agenesis of the corpus callosum and ventriculomegaly. Conclusions: Cytogenetic analysis or molecular techniques are necessary to establish the correct diagnosis in patients with multiple congenital anomalies in association with proximal or distal interstitial 14q deletion.

Atg5-mediated autophagy deficiency in proximal tubules promotes cell cycle G2/M arrest and renal fibrosis

ABSTRACTMacroautophagy/autophagy protects against cellular stress. Renal sublethal injury-triggered tubular epithelial cell cycle arrest at G2/M is associated with interstitial fibrosis. However, the role of autophagy in renal fibrosis is elusive. Here, we hypothesized that autophagy activity in tubular epithelial cells is pivotal for inhibition of cell cycle G2/M arrest and subsequent fibrogenic response. In both renal epithelial cells stimulated by angiotensin II (AGT II) and the murine kidney after unilateral ureteral obstruction (UUO), we observed that occurrence of autophagy preceded increased production of COL1 (collagen, type I). Pharmacological enhancement of autophagy by rapamycin suppressed COL1 accumulation and renal fibrosis. In contrast, genetic ablation of autophagy by proximal tubular epithelial cell-specific deletion of Atg5, with reduction of the LC3-II protein level and degradation of SQSTM1/p62, showed marked cell cycle arrest at the G2/M phase, robust COL1 deposition, and severe interstitial fibrosis in a UUO model, as compared with wild-type mice. In vitro, AGT II exposure triggered autophagy preferentially in the G1/S phase, and increased COL1 expression in the G2/M phase in renal epithelial cells. Stimulation of Atg5-deficient primary proximal tubular cells with AGT II also resulted in elevated G2/M arrest and COL1 production. Pharmacological or genetic inhibition of autophagy increased AGT II-mediated G2/M arrest. Enhanced expression of ATG5, but not the autophagy-deficient ATG5 mutant K130R, rescued the G2/M arrest, suggesting the regulation of cell cycle progression by ATG5 is autophagy dependent. In conclusion, Atg5-mediated autophagy in proximal epithelial cells is a critical host-defense mechanism that prevents renal fibrosis by blocking G2/M arrest.

De Novo Mutations of RERE Cause a Genetic Syndrome with Features that Overlap Those Associated with Proximal 1p36 Deletions

Deletions of chromosome 1p36 affect approximately 1 in 5,000 newborns and are associated with developmental delay, intellectual disability, and defects involving the brain, eye, ear, heart, and kidney. Arginine-glutamic acid dipeptide repeats (RERE) is located in the proximal 1p36 critical region. RERE is a widely-expressed nuclear receptor coregulator that positively regulates retinoic acid signaling. Animal models suggest that RERE deficiency might contribute to many of the structural and developmental birth defects and medical problems seen in individuals with 1p36 deletion syndrome, although human evidence supporting this role has been lacking. In this report, we describe ten individuals with intellectual disability, developmental delay, and/or autism spectrum disorder who carry rare and putatively damaging changes in RERE. In all cases in which both parental DNA samples were available, these changes were found to be de novo. Associated features that were recurrently seen in these individuals included hypotonia, seizures, behavioral problems, structural CNS anomalies, ophthalmologic anomalies, congenital heart defects, and genitourinary abnormalities. The spectrum of defects documented in these individuals is similar to that of a cohort of 31 individuals with isolated 1p36 deletions that include RERE and are recapitulated in RERE-deficient zebrafish and mice. Taken together, our findings suggest that mutations in RERE cause a genetic syndrome and that haploinsufficiency of RERE might be sufficient to cause many of the phenotypes associated with proximal 1p36 deletions.

Proximal tubule-specific glutamine synthetase deletion alters basal and acidosis-stimulated ammonia metabolism.

Glutamine synthetase (GS) catalyzes the recycling of NH4 (+) with glutamate to form glutamine. GS is highly expressed in the renal proximal tubule (PT), suggesting ammonia recycling via GS could decrease net ammoniagenesis and thereby limit ammonia available for net acid excretion. The purpose of the present study was to determine the role of PT GS in ammonia metabolism under basal conditions and during metabolic acidosis. We generated mice with PT-specific GS deletion (PT-GS-KO) using Cre-loxP techniques. Under basal conditions, PT-GS-KO increased urinary ammonia excretion significantly. Increased ammonia excretion occurred despite decreased expression of key proteins involved in renal ammonia generation. After the induction of metabolic acidosis, the ability to increase ammonia excretion was impaired significantly by PT-GS-KO. The blunted increase in ammonia excretion occurred despite greater expression of multiple components of ammonia generation, including SN1 (Slc38a3), phosphate-dependent glutaminase, phosphoenolpyruvate carboxykinase, and Na(+)-coupled electrogenic bicarbonate cotransporter. We conclude that 1) GS-mediated ammonia recycling in the PT contributes to both basal and acidosis-stimulated ammonia metabolism and 2) adaptive changes in other proteins involved in ammonia metabolism occur in response to PT-GS-KO and cause an underestimation of the role of PT GS expression.

Comparative deletion mapping at 1p31.3-p32.2 implies NFIA responsible for intellectual disability coupled with macrocephaly and the presence of several other genes for syndromic intellectual disability.

BackgroundWhile chromosome 1 is the largest chromosome in the human genome, less than two dozen cases of interstitial microdeletions in the short arm have been documented. More than half of the 1p microdeletion cases were reported in the pre-microarray era and as a result, the proximal and distal boundaries containing the exact number of genes involved in the microdeletions have not been clearly defined.ResultsWe revisited a previous case of a 10-year old female patient with a 1p32.1p32.3 microdeletion displaying syndromic intellectual disability. We performed microarray analysis as well as qPCR to define the proximal and distal deletion breakpoints and revised the karyotype from 1p32.1p32.3 to 1p31.3p32.2. The deleted chromosomal region contains at least 35 genes including NFIA. Comparative deletion mapping shows that this region can be dissected into five chromosomal segments containing at least six candidate genes (DAB1, HOOK1, NFIA, DOCK7, DNAJC6, and PDE4B) most likely responsible for syndromic intellectual disability, which was corroborated by their reduced transcript levels in RT-qPCR. Importantly, one patient with an intragenic microdeletion within NFIA and an additional patient with a balanced translocation disrupting NFIA display intellectual disability coupled with macrocephaly.ConclusionWe propose NFIA is responsible for intellectual disability coupled with macrocephaly, and microdeletions at 1p31.3p32.2 constitute a contiguous gene syndrome with several genes contributing to syndromic intellectual disability.

Possible role for nephron-derived angiotensinogen in angiotensin-II dependent hypertension.

The role of intranephron angiotensinogen (AGT) in blood pressure (BP) regulation is not fully understood. Previous studies showed that proximal tubule-specific overexpression of AGT increases BP, whereas proximal tubule-specific deletion of AGT did not alter BP. The latter study may not have completely eliminated nephron AGT production; in addition, BP was only assessed on a normal salt diet. To evaluate this issue in greater detail, we developed mice with inducible nephron-wide AGT deletion. Mice were generated which were hemizygous for the Pax8-rtTA and LC-1 transgenes and homozygous for loxP-flanked AGT alleles to achieve nephron-wide AGT disruption after doxycycline induction. Compared to controls, AGT knockout (KO) mice demonstrated markedly reduced renal AGT immunostaining, mRNA, and protein levels; unexpectedly AGT KO mice had reduced AGT mRNA levels in the liver along with 50% reduction in plasma AGT levels. BP was significantly lower in the AGT KO mice compared to controls fed a normal, low, or high Na(+) intake, with the highest BP reduction on a low Na(+) diet. Regardless of Na(+) intake, AGT KO mice had higher plasma renin concentration (PRC) and markedly reduced urinary AGT levels compared to controls. Following angiotensin-II (Ang-II) infusion, AGT KO mice demonstrated an attenuated hypertensive response despite similar suppression of PRC in the two groups. Taken together, these data suggest that nephron-derived AGT may be involved in Ang-II-dependent hypertension, however, a clear role for nephron-derived AGT in physiological BP regulation remains to be determined.

Simultaneous deletion of Bax and Bak is required to prevent apoptosis and interstitial fibrosis in obstructive nephropathy.

Proximal tubular injury and apoptosis are key mediators of the development of kidney fibrosis, a hallmark of chronic kidney disease. However, the molecular mechanism by which tubular apoptotic cell death leads to kidney fibrosis is poorly understood. In the present study, we tested the roles of Bcl-2-associated X (Bax) and Bcl-2 antagonist/killer (Bak), two crucial proteins involved in intrinsic apoptotic cell death, in the progression of kidney fibrosis. Mice with proximal tubule-specific Bax deletion, systemic deletion of Bak, and dual deletion of Bax and Bak were subjected to unilateral ureteral obstruction (UUO). Dual deficiency of Bax and Bak inhibited tubular apoptosis and atrophy. Consistent with decreased tubular injury, dual ablation of Bax and Bak suppressed UUO-induced inflammation and kidney fibrosis with decreased tubular cell cycle arrest, expression of fibrogenic and inflammatory cytokines, and oxidative stress in the kidney. Bax or Bak deficiency was insufficient to prevent apoptosis and all other aforementioned malevolent effects, suggesting compensatory mediation by each other in the respective signaling pathways. These data suggest that dual ablation of Bax and Bak in the kidney is required to prevent UUO-induced tubular apoptosis and the consequent kidney inflammation and fibrosis.

Genetic and Clinical Profile of Patients of Duchenne Muscular Dystrophy: Experience from a Tertiary Care Center in Eastern India.

To study the genetic pattern, clinical profile and to find any correlation between them in patients of Duchenne muscular dystrophy. Patients were selected from Neurogenetic clinic on the basis of clinical features, elevated serum CPK level and electromyographic features. After history and clinical examination, molecular genetic testing was performed by Polymerase Chain Reaction (PCR) technique. Among 100 patients, 73 patients had genetically confirmed disease while 8 cases were proven by biopsy, and thus a total 81 cases were further taken up for the study. Mean age of onset of clinical symptoms was 3.9 yrs; Valley sign and calf hypertrophy were most consistent features, while about 51% had facial weakness. Out of 73 genetically confirmed cases 53 (72.6%) showed deletion in distal exons and 12 (16.4%) showed deletion in both proximal and distal exons while 8 (10.9%) had only proximal deletion. There was no correlation between genetic pattern and clinical features. The positivity of PCR- based diagnosis is higher in our study possibly related to highly selective group of patients. Phenotype and genotype correlation was not seen.

Phosphatidylinositol 3-kinase signaling determines kidney size.

Kidney size adaptively increases as mammals grow and in response to the loss of 1 kidney. It is not clear how kidneys size themselves or if the processes that adapt kidney mass to lean body mass also mediate renal hypertrophy following unilateral nephrectomy (UNX). Here, we demonstrated that mice harboring a proximal tubule-specific deletion of Pten (Pten(ptKO)) have greatly enlarged kidneys as the result of persistent activation of the class I PI3K/mTORC2/AKT pathway and an increase of the antiproliferative signals p21(Cip1/WAF) and p27(Kip1). Administration of rapamycin to Pten(ptKO) mice diminished hypertrophy. Proximal tubule-specific deletion of Egfr in Pten(ptKO) mice also attenuated class I PI3K/mTORC2/AKT signaling and reduced the size of enlarged kidneys. In Pten(ptKO) mice, UNX further increased mTORC1 activation and hypertrophy in the remaining kidney; however, mTORC2-dependent AKT phosphorylation did not increase further in the remaining kidney of Pten(ptKO) mice, nor was it induced in the remaining kidney of WT mice. After UNX, renal blood flow and amino acid delivery to the remaining kidney rose abruptly, followed by increased amino acid content and activation of a class III PI3K/mTORC1/S6K1 pathway. Thus, our findings demonstrate context-dependent roles for EGFR-modulated class I PI3K/mTORC2/AKT signaling in the normal adaptation of kidney size and PTEN-independent, nutrient-dependent class III PI3K/mTORC1/S6K1 signaling in the compensatory enlargement of the remaining kidney following UNX.

3p14 De Novo Interstitial Microdeletion in a Patient with Intellectual Disability and Autistic Features with Language Impairment: A Comparison with Similar Cases.

To date, few cases of 3p proximal interstitial deletions have been reported and the phenotype and genotype correlation is not well understood. Here, we report a new case of a 3p proximal interstitial deletion. The patient is an 11-year-old female with speech and social interaction difficulties, learning disability, and slight facial dysmorphism, but no other major malformations. An 8 Mb de novo interstitial deletion at 3p14.2-p14.1, from position 60.461.316 to 68.515.453, was revealed by means of array comparative genomic hybridization and confirmed using quantitative reverse-transcription polymerase chain reaction assays. This region includes six genes: FEZF2, CADPS, SYNPR, ATXN7, PRICKLE, and MAGI1, that are known to have a role in neurodevelopment. These genes are located on the proximal side of the deletion. We compare our case with previously well-defined patients reported in the literature and databases.

G.P.174: Behavioral and neurocognitive profile in Duchenne Muscular Dystrophy

Non progressive cognitive impairment and increased rates psychosocial disorders, ADHD and Autism are reported in DMD patients. Through structured and validated questionnaire (Wechsler scales or Griffiths developmental scale, CBCL, Youth Self Report, Strengths and Difficulties Questionnaire, ADOS and DAWBA) we explored the possible role of cognitive impairment on the neuropsychiatric comorbidity in 32 boys with DMD (4–18years). Our preliminary analysis shows a mean Full Intelligence Quotient of the whole group of 83.90±16.68, lower in the patients with deletions in the distal portion of the gene (78.28±16.72) than in the ones with proximal deletions (88.52±15.62), with a very high frequency of Autism (about 20%) particularly in children with lower IQ level, and a high frequency of internalizing problems at CBCL, in boys with FIQ within the normal range, suggesting a role of cognitive capabilities in DMD children psychopathology.

Abstract 308: Nephron Specific Deletion Of Angiotensinogen Modulates Blood Pressure

It is unknown if intrarenal generation of angiotensinogen (AGT) is important in blood pressure (BP) regulation. Previous studies showed that proximal tubule-specific overexpression of AGT increases BP, while proximal tubule-specific deletion of AGT using the KAP promoter-Cre transgene did not alter BP. The latter study may not have completely eliminated nephron AGT production; in addition, BP was only assessed on a normal salt diet. To evaluate this issue in greater detail, we developed mice with inducible nephron-wide AGT deletion. Mice were generated which were hemizygous for the Pax8-rtTA and LC-1 transgenes and homozygous for loxP flanked AGT alleles to achieve nephron-specific AGT disruption after doxycycline induction. Adult Pax8-rtTA/LC-1/floxed AGT mice at 3 months of age were treated with doxycycline 2 mg/ml in drinking water for 11 days and studied 4 weeks after treatment. Blood pressure (recorded via telemetry) and metabolic balance studies were determined during 5 days of normal, high and low Na diets. Compared to controls, AGT knockout (KO) mice demonstrated significantly lower systolic, diastolic, and mean BPs on all three diets (N=4 each group). The BP reduction was most evident on a low Na diet (mean BP 107 ± 2 mmHg in controls and 88 ± 13 mmHg in AGT KO). Plasma renin concentration was higher in the AGT KO mice as compared to controls on all three diets. There were no detectable differences in weight, urine volume, urine osmolality or urine Na excretion between the controls and KO mice on all three diets, however due to variability, small differences in these parameters may not have been detected. Taken together, these data suggest that nephron AGT may contribute to BP regulation and this is most evident during low Na intake.

A newly recognized 13q12.3 microdeletion syndrome characterized by intellectual disability, microcephaly, and eczema/atopic dermatitis encompassing the HMGB1 and KATNAL1 genes

Proximal deletions of the long arm of chromosome 13 have been reported only rarely. Here we present three unrelated patients with heterozygous, apparently de novo deletions encompassing 13q12.3. The patients present with moderate demonstrated or apparent intellectual disability, postnatal microcephaly, and eczema/atopic dermatitis as the predominant symptoms. In addition, they had pronounced feeding difficulties in early infancy. They displayed similar facial features such as malar flattening, a prominent nose with underdeveloped alae nasi, a smooth philtrum, and a thin vermillion of the upper lip. The proximal and distal breakpoints were clustered and the deletions spanned from 1.4 to 1.7 Mb, comprising at least 11 RefSeq genes. However, heterozygous deletions partially overlapping those observed in the present patients have been described in healthy parents of patients with Peters-Plus syndrome, an autosomal recessive disorder caused by inactivation of the B3GALTL gene. We therefore propose that the critical region of the 13q12.3 microdeletion syndrome contains only three genes, namely, KATNAL1, HMGB1, and LINC00426, a non-protein coding RNA. The KATNAL1 protein belongs to a family of microtubule severing enzymes that have been implicated in CNS plasticity in experimental models, but little is known about its function in humans. The HMGB1 protein is an evolutionarily conserved chromatin-associated protein involved in many biologically important processes. In summary, we propose that microdeletion 13q12.3 represents a novel clinically recognizable condition and that the microtubule severing gene KATNAL1 and the chromatin-associated gene HMGB1 are candidate genes for intellectual disability inherited in an autosomal dominant pattern.

Metamorphic labral axis patterning in the beetle Tribolium castaneum requires multiple upstream, but few downstream, genes in the appendage patterning network

The arthropod labrum is an anterior appendage-like structure that forms the dorsal side of the preoral cavity. Conflicting interpretations of fossil, nervous system, and developmental data have led to a proliferation of scenarios for labral evolution. The best supported hypothesis is that the labrum is a novel structure that shares development with appendages as a result of co-option. Here, we use RNA interference in the red flour beetle Tribolium castaneum to compare metamorphic patterning of the labrum to previously published data on ventral appendage patterning. As expected under the co-option hypothesis, depletion of several genes resulted in similar defects in the labrum and ventral appendages. These include proximal deletions and proximal-to-distal transformations resulting from depletion of the leg gap genes homothorax and extradenticle, large-scale deletions resulting from depletion of the leg gap gene Distal-less, and smaller distal deletions resulting from knockdown of the EGF ligand Keren. However, depletion of dachshund and many of the genes that function downstream of the leg gap genes in the ventral appendages had either subtle or no effects on labral axis patterning. This pattern of partial similarity suggests that upstream genes act through different downstream targets in the labrum. We also discovered that many appendage axis patterning genes have roles in patterning the epipharyngeal sensillum array, suggesting that they have become integrated into a novel regulatory network. These genes include Notch, Delta, and decapentaplegic, and the transcription factors abrupt, bric à brac, homothorax, extradenticle and the paralogs apterous a and apterous b.

Repair of the 3' proximal and internal deletions of a satellite RNA associated with Cucumber mosaic virus is directed toward restoring structural integrity

The phenomenon of rapid turnover of 3' proximal nucleotides (nt) lost by the action of nuclease in RNA viruses is integral to replication. Here, a set of six deletions encompassing the 3' 23 nt region of a satellite RNA (satRNA) of Cucumber mosaic virus (CMV) strain Q (Q-sat), were engineered. Repair of the 3' end was not observed in the absence of CMV. However, co-expression with CMV in planta revealed that Q-sat mutants lacking the 3' 18 nt but not the 3' 23 nt are repaired and the progeny accumulation was inversely proportional to the extent of the deletion. Progeny of the 3'Δ3 mutant were repaired to wild type (wt) while those from the remaining four mutants were heterogeneous, exhibiting a wt secondary structure. Analysis of additional 3' internal deletions mutants revealed that progeny with a repaired sequence reminiscent of wt secondary structure were competent for replication and systemic spread.

1p36 Deletions in Two Cases with Thalassemia

ABSTRACTSummaryTerminal deletions in the short arm of chromosome one are generally associated with characteristic phenotype with dysmorphic features, including congenital anomalies and mental retardation with various degrees. Different outcomes depend on the sizes and locations of the deleted areas characterized by moderate to severe intellectual disability, delayed growth, hypotonia, seizures, limited speech ability, malformations, hearing and vision impairment and distinct facial features. The symptoms may vary, depending on the exact location of the chromosomal deletion but not a single reported case showed any ‘feature of anemia’.We report here one male and one female individual with partial deletions on chromosome no. one, both at 1p36 region. Cytogenetic analysis of blood lymphocytes was studied with high resolution GTG-banding analysis, using cyto-vision software on their chromosomes. Results revealed 46, XY, del(1)(p36.21) in the male who was also diagnosed as a ‘beta thalassemia trait’ and the other case was 46, XX, del(1)(p36.3) in the female who was diagnosed as a case of ‘HbE-beta thalassemia’.This report provides additional cases to the growing literature.Purpose/backgroundDeletion 1p36 is the most common terminal deletion syndrome with an estimated occurrence of 1:5000 live births. We report two patients with 1p36 deletions among which one shows ‘atypical’ proximal interstitial deletion at 1p36.21 using HR-GTG banding analysis. Interestingly, both the patients manifest one extra clinical characteristic that is different from those seen in ‘classical’ monosomy 1p36 syndrome, is ‘microcytic anemia’.Based on the analysis of the clinical and molecular data from our patients and those reported in the literature, we suggest that deletion 1p36.21 chromosomal abnormality may constitute yet another deletion syndrome distinct from the classical distal 1p36 deletion syndrome.Our aim was to find out further information regarding anemia since there are previously reported cases of anemias associated with this 1p36 region—one is presence of a ‘putative tumor suppressor gene’ important in the evolution of chronic myelocytic leukemia and the other is one inherited erythroblastopenia, commonly known as ‘Diamond-Blackfan anemia’ (DBA), caused by mutation in the gene encoding ribosomal protein L11 (RPL11) to answer families’ questions in the clinical setting.Materials and methodsStandard cytogenetic analysis was used with high resolution GTG-banding analysis, using cytovision software for karyotyping and high performance liquid chromatography (HPLC) and amplification refractory mutation mutation system (ARMS-PCR) to detect the five common Indian b-thalassemia mutations: [IVS-I-5 (G >C), Cod 15 (G-A), Cod 8/9 (+G), Fr 41/42 (–TTCT) and Cod 26 (G-A)].ResultsResults showed 46, XY, del(1)(p36.21) in the male, additionally diagnosed as a ‘beta thalassemia trait’ and in another case 46, XX, del(1)(p36.3) in female who was diagnosed as a case of ‘HbE-beta thalassemia’.ConclusionThese two patients with deletion 1p36 represent association with other genetic disorder which is characterized by hematological abnormalities.How to cite this articleDe P, Chakravarty S, Chakravarty A. 1p36 Deletions in Two Cases with Thalassemia. Int J Infertil Fetal Med 2014;5(2):69-74.