Leucine Repeat Research Articles

Overexpression of EcbHLH57 Transcription Factor from Eleusine coracana L. in Tobacco Confers Tolerance to Salt, Oxidative and Drought Stress.

Basic helix-loop-helix (bHLH) transcription factors constitute one of the largest families in plants and are known to be involved in various developmental processes and stress tolerance. We report the characterization of a stress responsive bHLH transcription factor from stress adapted species finger millet which is homologous to OsbHLH57 and designated as EcbHLH57. The full length sequence of EcbHLH57 consisted of 256 amino acids with a conserved bHLH domain followed by leucine repeats. In finger millet, EcbHLH57 transcripts were induced by ABA, NaCl, PEG, methyl viologen (MV) treatments and drought stress. Overexpression of EcbHLH57 in tobacco significantly increased the tolerance to salinity and drought stress with improved root growth. Transgenic plants showed higher photosynthetic rate and stomatal conductance under drought stress that resulted in higher biomass. Under long-term salinity stress, the transgenic plants accumulated higher seed weight/pod and pod number. The transgenic plants were also tolerant to oxidative stress and showed less accumulation of H202 and MDA levels. The overexpression of EcbHLH57 enhanced the expression of stress responsive genes such as LEA14, rd29A, rd29B, SOD, APX, ADH1, HSP70 and also PP2C and hence improved tolerance to diverse stresses.

Quantitative proteomics reveals the central changes of wheat in response to powdery mildew

Powdery mildew (Pm), caused by Blumeria graminis f. sp. tritici (Bgt), is one of the most important crop diseases, causing severe economic losses to wheat production worldwide. However, there are few reports about the proteomic response to Bgt infection in resistant wheat. Hence, quantitative proteomic analysis of N9134, a resistant wheat line, was performed to explore the molecular mechanism of wheat in defense against Bgt. Comparing the leaf proteins of Bgt-inoculated N9134 with that of mock-inoculated controls, a total of 2182 protein-species were quantified by iTRAQ at 24, 48 and 72h postinoculation (hpi) with Bgt, of which 394 showed differential accumulation. These differentially accumulated protein-species (DAPs) mainly included pathogenesis-related (PR) polypeptides, oxidative stress responsive proteins and components involved in primary metabolic pathways. KEGG enrichment analysis showed that phenylpropanoid biosynthesis, phenylalanine metabolism and photosynthesis-antenna proteins were the key pathways in response to Bgt infection. InterProScan 5 and the Gibbs Motif Sampler cluster 394 DAPs into eight conserved motifs, which shared leucine repeats and histidine sites in the sequence motifs. Moreover, eight separate protein–protein interaction (PPI) networks were predicted from STRING database. This study provides a powerful platform for further exploration of the molecular mechanism underlying resistant wheat responding to Bgt. SignificancePowdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a destructive pathogenic disease in wheat-producing regions worldwide, resulting in severe yield reductions. Although many resistant wheat varieties have been cultivated, there are few reports about the proteomic response to Bgt infection in resistant wheat. Therefore, an iTRAQ-based quantitative proteomic analysis of a resistant wheat line (N9134) in response to Bgt infection has been performed. This paper provides new insights into the underlying molecular mechanism of wheat in response to Bgt. The proteomic analysis can significantly narrow the field of potential defense-related protein-species, and is conducive to recognize the critical or effector protein under Bgt infection more precisely. Taken together, large amounts of high-throughput data provide a powerful platform for further exploration of the molecular mechanism on wheat–Bgt interactions.

Apoptosis Inhibitor 5 Increases Metastasis via Erk-mediated MMP expression.

Apoptosis inhibitor 5 (API5) has recently been identified as a tumor metastasis-regulating gene in cervical cancer cells. However, the precise mechanism of action for API5 is poorly understood. Here, we show that API5 increases the metastatic capacity of cervical cancer cells in vitro and in vivo via up-regulation of MMP-9. Interestingly, API5-mediated metastasis was strongly dependent on the Erk signaling pathway. Conversely, knock-down of API5 via siRNA technology decreased the level of phospho-Erk, the activity of the MMPs, in vitro invasion, and in vivo pulmonary metastasis. Moreover, the Erk-mediated metastatic action was abolished by the mutation of leucine into arginine within the heptad leucine repeat region, which affects protein-protein interactions. Thus, API5 increases the metastatic capacity of tumor cells by up-regulating MMP levels via activation of the Erk signaling pathway. [BMB Reports 2015; 48(6): 330-335]

A member of the Tlr family is involved in dsRNA innate immune response in Paracentrotus lividus sea urchin

The innate immune response involves proteins such as the membrane receptors of the Toll-like family (TLRs), which trigger different intracellular signalling pathways that are dependent on specific stimulating molecules. In sea urchins, TLR proteins are encoded by members of a large multigenic family composed of 60–250 genes in different species. Here, we report a newly identified mRNA sequence encoding a TLR protein (referred to as Pl-Tlr) isolated from Paracentrotus lividus immune cells. The partial protein sequence contained the conserved Toll/IL-1 receptor (TIR) domain, the transmembrane domain and part of the leucine repeats. Phylogenetic analysis of the Pl-Tlr protein was accomplished by comparing its sequence with those of TLRs from different classes of vertebrates and invertebrates. This analysis was suggestive of an evolutionary path that most likely represented the course of millions of years, starting from simple organisms and extending to humans. Challenge of the sea urchin immune system with poly-I:C, a chemical compound that mimics dsRNA, caused time-dependent Pl-Tlr mRNA up-regulation that was detected by QPCR. In contrast, bacterial LPS injury did not affect Pl-Tlr transcription. The study of the Tlr genes in the sea urchin model system may provide new perspectives on the role of Tlrs in the invertebrate immune response and clues concerning their evolution in a changing world.

Extracellular matrix disruption is an early event in the pathogenesis of skeletal disease in mucopolysaccharidosis I

Progressive skeletal and connective tissue disease represents a significant clinical burden in all of the mucopolysaccharidoses. Despite the introduction of enzyme replacement strategies for many of the mucopolysaccharidoses, symptomatology related to bone and joint disease appears to be recalcitrant to current therapies. In order to address these unmet medical needs a clearer understanding of skeletal and connective tissue disease pathogenesis is required. Historically the pathogenesis of the mucopolysaccharidoses has been assumed to directly relate to progressive storage of glycosaminoglycans. It is now apparent for many lysosomal storage disorders that more complex pathogenic mechanisms underlie patients' clinical symptoms. We have used proteomic and genome wide expression studies in the murine mucopolysaccharidosis I model to identify early pathogenic events occurring in micro-dissected growth plate tissue. Studies were conducted using 3 and 5-week-old mice thus representing a time at which no obvious morphological changes of bone or joints have taken place. An unbiased iTRAQ differential proteomic approach was used to identify candidates followed by validation with multiple reaction monitoring mass spectrometry and immunohistochemistry. These studies reveal significant decreases in six key structural and signaling extracellular matrix proteins; biglycan, fibromodulin, PRELP, type I collagen, lactotransferrin, and SERPINF1. Genome-wide expression studies in embryonic day 13.5 limb cartilage and 5week growth plate cartilage followed by specific gene candidate qPCR studies in the 5week growth plate identified fourteen significantly deregulated mRNAs (Adamts12, Aspn, Chad, Col2a1, Col9a1, Hapln4, Lum, Matn1, Mmp3, Ogn, Omd, P4ha2, Prelp, and Rab32). The involvement of biglycan, PRELP and fibromodulin; all members of the small leucine repeat proteoglycan family is intriguing, as this protein family is implicated in the pathogenesis of late onset osteoarthritis. Taken as a whole, our data indicates that alteration of the extracellular matrix represents a very early event in the pathogenesis of the mucopolysaccharidoses and implies that biomechanical failure of chondro-osseous tissue may underlie progressive bone and joint disease symptoms. These findings have important therapeutic implications.

Adaptor Protein LRAP25 Mediates Myotonic Dystrophy Kinase-related Cdc42-binding Kinase (MRCK) Regulation of LIMK1 Protein in Lamellipodial F-actin Dynamics

Myotonic dystrophy kinase-related Cdc42-binding kinase (MRCK) has been shown to localize to the lamella of mammalian cells through its interaction with an adaptor protein, leucine repeat adaptor protein 35a (LRAP35a), which links it with myosin 18A (MYO18A) for activation of the lamellar actomyosin network essential for cell migration. Here, we report the identification of another adaptor protein LRAP25 that mediates MRCK association with LIM kinase 1 (LIMK1). The lamellipodium-localized LRAP25-MRCK complex is essential for the regulation of local LIMK1 and its downstream F-actin regulatory factor cofilin. Functionally, inhibition of either MRCK or LRAP25 resulted in a marked suppression of LIMK1 activity and down-regulation of cofilin phosphorylation in response to aluminum fluoride induction in B16-F1 cells, which eventually resulted in deregulation of lamellipodial F-actin and reorganization of cytoskeletal structures causing defects in cell polarization and motility. These biochemical and functional characterizations thus underline the functional relevance of the LRAP25-MRCK complex in LIMK1-cofilin signaling and the importance of LRAP adaptors as key determinants of MRCK cellular localization and downstream specificities.

Functional characterization of genetic variants in the porcine TLR3 gene

Toll-like receptor 3 (TLR3) recognizes double-stranded RNA, which is a molecular signature of viruses, and plays a pivotal role in host defense against viral invasion. Polymorphisms in the human TLR3 gene have been shown to affect the receptor function and to be associated with a variety of diseases, suggesting correlations between TLR3 polymorphisms and the disease resistance/susceptibility in pigs. In this study, 5 known non-synonymous single nucleotide polymorphisms (SNPs) in the coding sequences of the porcine TLR3 gene - c.800C>T (p.T267M), c.933A>G (p.I311M), c.1116A>T (p.K372N), c.2129C>G (p.T710S), and c.2160T>G (p.I720M) - were analyzed for their effect on receptor function in transiently transfected PK-15 cells by using a luciferase reporter assay. In addition, the distribution of SNP c.933A>G was analyzed among pig populations. SNP c.933A>G significantly decreased the response to poly(I:C) (P < 0.05), as represented by the weaker induction of firefly luciferase relative to that achieved by wild-type TLR3. SNP c.933A>G results in the alteration of conserved amino acids in the highly conserved segment of the 12th leucine repeat region and is conserved among TLR3 orthologs from fishes to primates. Moreover, together with the results of previous studies, the results of the present study revealed that SNP c.933A>G is found solely in local Chinese pig breeds. These results suggested that SNP c.933A>G plays a role in porcine disease resistance/susceptibility.

The Influence of a Single Nucleotide Polymorphism within CNDP1 on Susceptibility to Diabetic Nephropathy in Japanese Women with Type 2 Diabetes

BackgroundSeveral linkage analyses have mapped a susceptibility locus for diabetic nephropathy to chromosome 18q22–23, and polymorphisms within the carnosine dipeptidase 1 gene (CNDP1), located on 18q22.3, have been shown to be associated with diabetic nephropathy in European subjects with type 2 diabetes. However, the association of this locus with diabetic nephropathy has not been evaluated in the Japanese population. In this study, we examined the association of polymorphisms within the CNDP1/CNDP 2 locus with diabetic nephropathy in Japanese subjects with type 2 diabetes.Methodology/Principal FindingsWe genotyped a leucine repeat polymorphism (D18S880) that is within CNDP1 along with 29 single nucleotide polymorphisms (SNPs) in the CNDP1/CNDP2 locus for 2,740 Japanese subjects with type 2 diabetes (1,205 nephropathy cases with overt nephropathy or with end-stage renal disease [ESRD], and 1,535 controls with normoalbuminuria). The association of each polymorphism with diabetic nephropathy was analysed by performing logistic regression analysis. We did not observe any association between D18S880 and diabetic nephropathy in Japanese subjects with type 2 diabetes. None of the 29 SNPs within the CNDP1/CNDP2 locus were associated with diabetic nephropathy, but a subsequent sex-stratified analysis revealed that 1 SNP in CNDP1 was nominally associated with diabetic nephropathy in women (rs12604675-A; p = 0.005, odds ratio [OR] = 1.76, 95% confidence interval [CI], 1.19−2.61). Rs12604675 was associated with overt proteinuria (p = 0.002, OR = 2.18, 95% CI, 1.32−3.60), but not with ESRD in Japanese women with type 2 diabetes.Conclusions/SignificanceRs12604675-A in CNDP1 may confer susceptibility to overt proteinuria in Japanese women with type 2 diabetes.

The role of PHLPP in regulating cell migration in pancreatic cancer

Pancreatic cancer is the fourth leading cause of cancer in the United States. However, it has the worse prognosis of any malignancy with a 4% 5 year survival rate. Contributing factors include but not limited to late stage diagnosis due to vague symptoms and the degree of aggression associated with this type of cancer. Surgical resection is impossible in 50% of cases due to the advanced stage at the time of diagnosis. Pancreatic Ductal Adenocarcinoma (PDA) has a high rate of chemotherapy and radiation resistance increasing the need for innovative treatment modalities. Hyperactivation of PI3K/Akt pathways is commonly associated with many types of human cancers including pancreatic cancer. Recently, we have identified a novel protein phosphatase, PHLPP (PH domain Leucine repeat Protein Phosphatase) that dephosphorylates Akt and terminates Akt signaling directly. Our previous studies show that loss of PHLPP expression results in an increase in cell proliferation and a decrease in apoptosis. Here, we investigate the role of both PHLPP isoforms namely PHLPP1 and PHLPP2 in regulating pancreatic cancer cell migration and metastasis. Stable pancreatic cancer cell lines were generated using lentivirus‐based shRNAs to knockdown endogenous PHLPP expression. Alteration of Akt‐mediated signaling is analyzed in PHLPP knockdown cells. In addition, cell migration and invasion assays are performed to determine if loss of PHLPP expression promotes both tumorigenesis and metastasis in pancreatic cancer. The knowledge gained in these studies will provide a novel therapeutic avenue using PHLPP as a potential target.Funded by NIH R01CA133429, and American Cancer Society RSG0822001TBE.

The socs box—adapting proteins for ubiquitination and proteasomal degradation

AbstractThe suppressor of cytokine signalling (SOCS) box was first identified in the SH2‐containing SOCS box family (cytokine‐inducible SH2‐containing protein, SOCS1–7) and is a 40‐amino acid motif, which functions to recruit an E3 ubiquitin ligase complex consisting of the adapter proteins elongins B and C, Rbx2 and the scaffold protein Cullin5. The SOCS box is found in a diverse array of intracellular signalling molecules, many of which contain different protein interaction domains such as SPRY and WD40 domains, leucine and ankyrin repeats or other functional domains such as GTPases. In general, the SOCS box‐containing proteins are thought to act as substrate‐recognition modules to mediate the polyubiquitination and subsequent degradation of substrate proteins by the 26S proteasome. © 2012 IUBMB IUBMB Life, 2012

Helical Repeat Structure of Apoptosis Inhibitor 5 Reveals Protein-Protein Interaction Modules

Apoptosis inhibitor 5 (API5) is an anti-apoptotic protein that is up-regulated in various cancer cells. Here, we present the crystal structure of human API5. API5 exhibits an elongated all α-helical structure. The N-terminal half of API5 is similar to the HEAT repeat and the C-terminal half is similar to the ARM (Armadillo-like) repeat. HEAT and ARM repeats have been implicated in protein-protein interactions, suggesting that the cellular roles of API5 may be to mediate protein-protein interactions. Various components of multiprotein complexes have been identified as API5-interacting protein partners, suggesting that API5 may act as a scaffold for multiprotein complexes. API5 exists as a monomer, and the functionally important heptad leucine repeat does not exhibit the predicted a dimeric leucine zipper. Additionally, Lys-251, which can be acetylated in cells, plays important roles in the inhibition of apoptosis under serum deprivation conditions. The acetylation of this lysine also affects the stability of API5 in cells.

The SOCS box—Adapting proteins for ubiquitination and proteasomal degradation

The suppressor of cytokine signalling (SOCS) box was first identified in the SH2-containing SOCS box family (cytokine-inducible SH2-containing protein, SOCS1-7) and is a 40-amino acid motif, which functions to recruit an E3 ubiquitin ligase complex consisting of the adapter proteins elongins B and C, Rbx2 and the scaffold protein Cullin5. The SOCS box is found in a diverse array of intracellular signalling molecules, many of which contain different protein interaction domains such as SPRY and WD40 domains, leucine and ankyrin repeats or other functional domains such as GTPases. In general, the SOCS box-containing proteins are thought to act as substrate-recognition modules to mediate the polyubiquitination and subsequent degradation of substrate proteins by the 26S proteasome.

Guide to virtual screening: application to the Akt phosphatase PHLPP.

We present an example-based description of virtual screening (VS) techniques used to identify new regulators of the Akt phosphatase PHLPP (PH domain Leucine repeat Protein Phosphatase). This enzyme opposes the effects of two kinases, Akt and PKC, which play a major role in cell growth and survival. Therefore, PHLPP is a potential therapeutic target in pathophysiologies where these pathways are either repressed, such as in diabetes and cardiovascular diseases, or over-activated as in cancer. To the best of our knowledge, no PHLPP inhibitors have been reported so far in the literature. In this study, we used a combination of chemical and virtual screening techniques that led to the identification of a number of inhibiting compounds with diverse scaffolds. These compounds bind PHLPP and inhibit cell death when tested in cellular assays. We employed GLIDE docking software to screen a library of more than 40,000 compounds selected from the NCI open depository (250,000 compounds) by similarity searches. We compare the efficiency at which we determined binding compounds from the chemical screen, and compare enrichment factors of the virtually discovered compounds over chemical screening.

ProRepeat: an integrated repository for studying amino acid tandem repeats in proteins

ProRepeat (http://prorepeat.bioinformatics.nl/) is an integrated curated repository and analysis platform for in-depth research on the biological characteristics of amino acid tandem repeats. ProRepeat collects repeats from all proteins included in the UniProt knowledgebase, together with 85 completely sequenced eukaryotic proteomes contained within the RefSeq collection. It contains non-redundant perfect tandem repeats, approximate tandem repeats and simple, low-complexity sequences, covering the majority of the amino acid tandem repeat patterns found in proteins. The ProRepeat web interface allows querying the repeat database using repeat characteristics like repeat unit and length, number of repetitions of the repeat unit and position of the repeat in the protein. Users can also search for repeats by the characteristics of repeat containing proteins, such as entry ID, protein description, sequence length, gene name and taxon. ProRepeat offers powerful analysis tools for finding biological interesting properties of repeats, such as the strong position bias of leucine repeats in the N-terminus of eukaryotic protein sequences, the differences of repeat abundance among proteomes, the functional classification of repeat containing proteins and GC content constrains of repeats’ corresponding codons.

Specific Expression of a Novel Nodulin GmN479 Gene in the Infected Cells of Soybean (Glycine max) Nodules

Abstract A novel nodulin gene, GmN479 genomic clone composing of 3 630 nucleotides was isolated from mature soybean nodules using GmN479 cDNA as a probe by subtractive hybridization procedure. GmN479 encodes 170 amino acids with 2.09 kb nucleotides promoter region, and contains two important upstream promoter elements, one is a conserved “s-acting sequence motif 5′-AAAGAT-3′ controlling nodulin gene expression, and the other is typical CAAT boxes. GmN479 gene has a single zmc-fmger C 2H 2 domain YS CAF CQRGFSNAQALLGG HMNI H and a conserved motif, QALGGHMN m the zinc-finger with a short leucine repeat in the LDLELRLGL motif closed to C-terminal. These two conserved motifs share respectively higher identity with those in the floral regulator SUPERMAN gene, indicating that GmN479 may function as a transcriptional regulator, and is a likely candidate for playing a role in nodule-morphogenesis. Blotting data showed that GmN479 is a single copy presenting in the genome of soybean nodule, and its expression profile is similar to that of Lb-a, but it is different from that of ENOD2. GUS staining showed that GmN479 promoter just functions in the infected cells of nodules, indicating that the GmN479 is one of the truly symbiotically induced host genes, and belongs to a late nodulin gene. The expression pattern of GmN479 gene seems to imply that it may be closely related to the development of the nodule. In a sense, it may be a useful marker for identifying the development of the infected cell system in the nodules of soybean.

Leucine 10 allelic variant in signal peptide of PCSK9 increases the LDL cholesterol-lowering effect of statins in patients with familial hypercholesterolaemia

Background and aimsIn the normal population, carriers of an additional leucine residue in a stretch of nine leucines in the signal peptide of PCSK9 (L10) have lower total (TC) and low-density lipoprotein cholesterol (LDL-C) than homozygotes for the wild-type allele (L9/L9). A similar effect was detected in familial hypercholesterolaemia (FH) patients with the p.C681X mutation of LDL-receptor (LDLR). We investigated the effect of L10 variant on basal lipid profile and response to statins in molecularly characterised FH patients. Methods and resultsPlasma lipids were determined in 322 FH patients screened for the L9/L10/L11 polymorphism and in a subgroup of 54 patients carrying the same LDLR mutation (p.Q474HfsX63). Plasma lipids were also determined in 42 FH patients carrying the L10 variant and in a parallel group of 42 FH patients, L9/L9 homozygotes, matched for gender, age, type of LDLR gene mutation, as well as for type, dose and duration of statin treatment. In FH patients, no difference in the basal plasma TC and LDL-C levels was observed between carriers of L10 variant (L9/L10+L10/L10) and L9/L9 homozygotes. The same was true in FH patients carrying the p.Q474HfsX63 LDLR mutation. In the subgroups of statin-treated patients, the reduction of TC and LDL-C was greater in carriers of L10 (−34.0% and −42.5%, respectively) than in L9/L9 homozygotes (−27.5% and −34.3%, respectively) (P<0.001). ConclusionThe variant L10 of the leucine repeats in PCSK9 signal peptide is to be considered as a factor capable of modulating the lipid-lowering effects of statins in FH.

Common variants in CNDP1 and CNDP2, and risk of nephropathy in type 2 diabetes

Several genome-wide linkage studies have shown an association between diabetic nephropathy and a locus on chromosome 18q harbouring two carnosinase genes, CNDP1 and CNDP2. Carnosinase degrades carnosine (β-alanyl-L-histidine), which has been ascribed a renal protective effect as a scavenger of reactive oxygen species. We investigated the putative associations of genetic variants in CNDP1 and CNDP2 with diabetic nephropathy (defined either as micro- or macroalbuminuria) and estimated GFR in type 2 diabetic patients from Sweden. We genotyped nine single nucleotide polymorphisms (SNPs) and one trinucleotide repeat polymorphism (D18S880, five to seven leucine repeats) in CNDP1 and CNDP2 in a case-control set-up including 4,888 unrelated type 2 diabetic patients (with and without nephropathy) from Sweden (Scania Diabetes Registry). Two SNPs, rs2346061 in CNDP1 and rs7577 in CNDP2, were associated with an increased risk of diabetic nephropathy (rs2346061 p = 5.07 × 10(-4); rs7577 p = 0.021). The latter was also associated with estimated GFR (β = -0.037, p = 0.014), particularly in women. A haplotype including these SNPs (C-C-G) was associated with a threefold increased risk of diabetic nephropathy (OR 2.98, 95% CI 2.43-3.67, p < 0.0001). These data suggest that common variants in CNDP1 and CNDP2 play a role in susceptibility to kidney disease in patients with type 2 diabetes.

Relationship between carnosinase gene CNDP1 leucine repeat polymorphism and the clinical outcome of Chinese PD patients

pre-clinical studies showed that carnosine may have a beneficial cardiovascular effect. We studied the effect of tri-nucleotide repeat (CTGs) polymorphisms in exon 2 of the CNDP1 gene, which codes for carnosinase and is responsible for the degradation of carnosine, on the clinical outcome of Chinese peritoneal dialysis (PD) patients. we studied 442 PD subjects. Genotyping was done by direct sequencing of genomic DNA. Patients were followed for 43.5 ± 16.2 months. the prevalence of 6-6, 5-6, 5-5 and 4-6 CTGs genotypes was 80.3%, 18.6%, 0.9% and 0.2%, respectively. A total of 270 patients (61.1%) developed the primary composite end point during follow-up. The 5-year event-free survival of the 6-6 CTGs and non 6-6 group was 37.1% and 21.3%, respectively (log rank test, p = 0.3). the CTGs polymorphism of the CNDP1 gene does not affect survival of Chinese PD subjects. The role of carnosine and CNDP1 gene polymorphism in the pathogenesis of cardiovascular disease requires further study.

LOW DISEASE RISK IN RELATIVES OF NORTH AFRICAN LRRK2 PARKINSON DISEASE PATIENTS

Currently, mutations in the leucine repeat–rich kinase 2 (LRRK2) gene are the main identifiable genetic cause of Parkinson disease (PD). The Gly2019Ser (G2019S) substitution is the most common mutation and is frequent among North African (40%) and Jewish (30%) patients with familial PD. Reduced G2019S penetrance has been documented in several reports.1–3 The identification of LRRK2 mutations in numerous North African patients without PD family history prompted us to investigate disease risk in presumed mutation carriers in this population. ### Methods. PD cases were recruited by a national French network (French PD Genetic Study Group) and collaborators from Algeria at their outpatient clinic (September 1994 through August 2007). Blood samples were collected from participants after obtaining written informed consent, and molecular analyses were performed.4 For this study, we included probands of North African ancestry who were heterozygous or homozygous G2019S carriers (figure e-1 on the Neurology ® Web site at www.neurology.org). They were interviewed to obtain information on their first-degree relatives. Relatives were analyzed from birth through 1 of the following events, whichever occurred first: PD onset or last contact or death without PD. The cumulative risk of PD until age 80 years in first-degree relatives was estimated using the Kaplan-Meier …

A polymorphism in the gene encoding carnosinase (CNDP1) as a predictor of mortality and progression from nephropathy to end-stage renal disease in type 1 diabetes mellitus

Aims/hypothesisHomozygosity for a five leucine repeat (5L–5L) in the carnosinase gene (CNDP1) has been found to be cross-sectionally associated with a low frequency of diabetic nephropathy (DN), mainly in type 2 diabetes. We prospectively investigated in patients with type 1 diabetes whether: (1) 5L–5L is associated with mortality; (2) there is an interaction of 5L–5L with DN or sex for prediction of mortality; and (3) 5L–5L is associated with progression to end-stage renal disease (ESRD).MethodsIn this prospective study in white European patients with type 1 diabetes, individuals with DN were defined by persistent albuminuria ≥300 mg/24 h. Controls without nephropathy were defined by persistent (>15 years) normoalbuminuria <30 mg/24 h. Leucine repeats were assessed with a fluorescent DNA analysis system. Onset of ESRD was defined by need to start chronic dialysis or kidney transplantation.ResultsThe study involved 916 patients with DN and 1,170 controls. During follow-up for 8.8 years, 107 patients (14%) with 5L–5L died compared with 182 patients (13.8%) with other genotypes (p = 0.99). There was no significant interaction of 5L–5L with DN for prediction of mortality (p = 0.57), but a trend towards interaction with sex (p = 0.08). In patients with DN, HR for ESRD in 5L–5L vs other genotypes was not constant over time, with increased risk for 5L–5L beyond 8 years of follow-up (p = 0.03).Conclusions/interpretation CNDP1 polymorphism was not associated with mortality, and nor was there an interaction of this polymorphism with DN for prediction of mortality in patients with type 1 diabetes. CNDP1 polymorphism predicts progression to ESRD in patients with DN, but only late after baseline measurements.Electronic supplementary materialThe online version of this article (doi:10.1007/s00125-010-1863-0) contains supplementary material, which is available to authorised users.