Characterisation and differential expression during development of a duplicate Disabled-1 (Dab1) gene from zebrafish

We identified a new duplicated Dab1 gene (drDab1b) spanning around 25 kb of genomic DNA in zebrafish. Located in zebrafish chromosome 2, it is composed of 11 encoding exons and shows high sequence similarity to other Dab1 genes, including drDab1a, a zebrafish Dab1 gene previously characterised. drDab1b encodes by alternative splicing at least five different isoforms. Both drDab1a and drDab1b show differential gene expression levels in distinct adult tissues and during development. drDab1b is expressed in peripheral tissues (gills, heart, intestine, muscle), the immune system (blood, liver) and the central nervous system (CNS), whereas drDab1a is only expressed in gills, muscle and the CNS, suggesting a division of functions for two Dab1 genes in zebrafish adult tissues. RT-PCR analysis also reveals that both drDab1 genes show distinct developmental-specific expression patterns throughout development. drDab1b expression was higher than that of drDab1a, suggesting a major role of drDab1b in comparison with drDab1a during development and in different adult tissues. In addition, new putative Dab1 (a and/or b) from different teleost species were identified in silico and predicted protein products are compared with the previously characterised Dab1, demonstrating that the Dab1b group is more ancestral than their paralogue, the Dab1a group.     

Function of tau protein in adult newborn neurons

Levels of tau phosphorylation are high during the developmental period of intense neurite outgrowth, but decrease later. We here investigated whether tau protein plays a role in adult neurogenesis. First we demonstrate that new neurons generated in the subgranular zone express tau in a hyperphosphorylated form. Phospho-tau expression colocalized with doublecortin but not with glial fibrillary acidic protein, Ki67 or calbindin. The same was observed in the subventricular zone. Tau knockout mice did not show a significant decrease in the number of doublecortin-positive cells, although a deficit in migration was observed. These findings suggest that basal tau phosphorylation present in adult animals is in part due to neurogenesis, and from Tau knockout mice it seems that tau is involved in normal migration of new neurons.     

Arabidopsis TRANSCURVATA1 Encodes NUP58, a Component of the Nucleopore Central Channel

The selective trafficking of proteins and RNAs through the nuclear envelope regulates nuclear-cytoplasmic segregation of macromolecules and is mediated by nucleopore complexes (NPCs), which consist of about 400 nucleoporins (Nups) of about 30 types. Extensive studies of nucleoporin function in yeast and vertebrates showed that Nups function in nucleocytoplasmic trafficking and other processes. However, limited studies of plant Nups have identified only a few mutations, which cause pleiotropic phenotypes including reduced growth and early flowering. Here, we describe loss-of-function alleles of Arabidopsis TRANSCURVATA1 (TCU1); these mutations cause increased hypocotyl and petiole length, reticulate and asymmetrically epinastic leaf laminae of reduced size, and early flowering. TCU1 is transcribed in all of the organs and tissues examined, and encodes the putative ortholog of yeast and vertebrate Nup58, a nucleoporin of the Nup62 subcomplex. Nup58 forms the central channel of the NPC and acts directly in translocation of proteins through the nuclear envelope in yeast and vertebrates. Yeast two-hybrid (Y2H) assays identified physical interactions between TCU1/NUP58 and 34 proteins, including nucleoporins, SCF (Skp1/Cul1/F-box) ubiquitin ligase complex components and other nucleoplasm proteins. Genetic interactions were also found between TCU1 and genes encoding nucleoporins, soluble nuclear transport receptors and components of the ubiquitin-proteasome and auxin signaling pathways. These genetic and physical interactions indicate that TCU1/NUP58 is a member of the Nup62 subcomplex of the Arabidopsis NPC. Our findings also suggest regulatory roles for TCU1/NUP58 beyond its function in nucleocytoplasmic trafficking, a hypothesis that is supported by the Y2H and genetic interactions that we observed.     

Guía de práctica clínica para el diagnóstico y tratamiento de la apoplejía hipofisaria

Classic pituitary apoplexy (PA) is an acute, life-threatening clinical syndrome caused by acute hemorrhage and/or infarction of the pituitary gland. PA is considered a neuroendocrinological emergency. However, there is no consensus about the best options for PA diagnosis and management.ObjectiveTo develop a clinical practice guideline with a number of recommendations for diagnosis and treatment of patients with PA based on the medical evidence available, in order to help clinicians involved in their care.MethodsThe clinical guideline for diagnosis and treatment of pituitary apoplexy issued in 2006 by the Neuroendocrinology Working Group of the Spanish Society of Endocrinology and Nutrition (SEEN) and the British Clinical Practice Guideline published in 2011 were taken as the basis. The text has been adapted to the format used in most international medical journals. For this, after updated medical literature, the quality of evidence and the strength of the recommendations were evaluated using the system proposed by the Agency for Health Care Policy and Research (AHCPR).ConclusionsDiagnosis of pituitary apoplexy should be considered in all patients with acute severe headache with or without neuro-ophthalmic signs. Patients with PA must undergo a complete history and physical examination. All patients with suspected pituitary apoplexy should have urgent blood samples drawn to test electrolytes, renal function, liver function, coagulation screen, complete blood count, and basal levels of pituitary and peripheral hormones, and to rule out adrenocorticotropic hormone (ACTH) deficiency. Formal visual field assessment should be performed when the patient is clinically stable. Magnetic resonance imaging (MRI) is the imaging test of choice to confirm diagnosis. Indications for empirical urgent corticosteroid therapy in patients with PA include hemodynamic instability, impaired consciousness, reduced visual acuity, and severe visual field defects. In patients with these severe neuro-ophthalmic signs, surgery should be considered. Surgery should preferably be performed within seven days of the onset of symptoms. Patients with mild and stable signs may be managed conservatively with careful monitoring. Treatment and long-term follow-up of patients with PA should be conducted by a multidisciplinary team consisting, amongst others, of an experienced pituitary neurosurgeon, an ophthalmologist, and an endocrinologist.     

Mutations in IMPG1 Cause Vitelliform Macular Dystrophies

Vitelliform macular dystrophies (VMD) are inherited retinal dystrophies characterized by yellow, round deposits visible upon fundus examination and encountered in individuals with juvenile Best macular dystrophy (BMD) or adult-onset vitelliform macular dystrophy (AVMD). Although many BMD and some AVMD cases harbor mutations in BEST1 or PRPH2, the underlying genetic cause remains unknown for many affected individuals. In a large family with autosomal-dominant VMD, gene mapping and whole-exome sequencing led to the identification of a c.713T>G (p.Leu238Arg) IMPG1 mutation, which was subsequently found in two other families with autosomal-dominant VMD and the same phenotype. IMPG1 encodes the SPACR protein, a component of the rod and cone photoreceptor extracellular matrix domains. Structural modeling indicates that the p.Leu238Arg substitution destabilizes the conserved SEA1 domain of SPACR. Screening of 144 probands who had various forms of macular dystrophy revealed three other IMPG1 mutations. Two individuals from one family affected by autosomal-recessive VMD were homozygous for the splice-site mutation c.807+1G>T, and two from another family were compound heterozygous for the mutations c.461T>C (p.Leu154Pro) and c.1519C>T (p.Arg507^∗). Most cases had a normal or moderately decreased electrooculogram Arden ratio. We conclude that IMPG1 mutations cause both autosomal-dominant and -recessive forms of VMD, thus indicating that impairment of the interphotoreceptor matrix might be a general cause of VMD.     

Met signaling in cardiomyocytes is required for normal cardiac function in adult mice

Hepatocyte growth factor (HGF) and its receptor, Met, are key determinants of distinct developmental processes. Although HGF exerts cardio-protective effects in a number of cardiac pathologies, it remains unknown whether HGF/Met signaling is essential for myocardial development and/or physiological function in adulthood. We therefore investigated the requirement of HGF/Met signaling in cardiomyocyte for embryonic and postnatal heart development and function by conditional inactivation of the Met receptor in cardiomyocytes using the Cre-α-MHC mouse line (referred to as α-MHCMet-KO). Although α-MHCMet-KO mice showed normal heart development and were viable and fertile, by 6 months of age, males developed cardiomyocyte hypertrophy, associated with interstitial fibrosis. A significant upregulation in markers of myocardial damage, such as β-MHC and ANF, was also observed. By the age of 9 months, α-MHCMet-KO males displayed systolic cardiac dysfunction. Mechanistically, we provide evidence of a severe imbalance in the antioxidant defenses in α-MHCMet-KO hearts involving a reduced expression and activity of catalase and superoxide dismutase, with consequent reactive oxygen species accumulation. Similar anomalies were observed in females, although with a slower kinetics. We also found that Met signaling down-regulation leads to an increase in TGF-β production and a decrease in p38MAPK activation, which may contribute to phenotypic alterations displayed in α-MHCMet-KO mice. Consistently, we show that HGF acts through p38α to upregulate antioxidant enzymes in cardiomyocytes. Our results highlight that HGF/Met signaling in cardiomyocytes plays a physiological cardio-protective role in adult mice by acting as an endogenous regulator of heart function through oxidative stress control.     

Construction of an Expression Vector for Production and Purification of Human Somatostatin in Escherichia coli

Cassava mosaic disease, caused by cassava mosaic geminiviruses are transmitted by Bemisia tabaci. The B. tabaci adults from colonies reared on virus free cassava plant produced from apical meristem culture was studied to determine their ability to transmit Indian cassava mosaic virus (ICMV) and Sri Lankan cassava mosaic virus (SLCMV) from cassava to cassava. Virus free plants were confirmed by polymerase chain reaction (PCR) using geminivirus degenerate primers. The virus acquisition access period (AAP) of 48 h on virus infected cassava leaves and 48 h virus inoculation access periods on virus free healthy leaves were investigated. Both ICMV and SLCMV were absolutely transmitted by whiteflies reared on cassava. Virus specific primers were designed in the replicase region and used to detect virus in B. tabaci after different AAP. The PCR amplified replicase genes from virus transmitted cassava leaves were cloned the plasmid DNA was isolated from a recombinant colony of E. coli DH5α after their confirmation by colony PCR and sequenced them. The nucleotide sequences obtained from automated DNA sequencing were confirmed as ICMV and SLCMV replicase gene after homology searching by BLAST and found to be a new isolates. The nucleotide sequences of new isolates were submitted in GenBank (accession number JN652126 and JN595785).