MCM9 Is Required for Mammalian DNA Mismatch Repair

International audienceDNA mismatch repair (MMR) is an evolutionarily conserved process that corrects DNA polymerase errors during replication to maintain genomic integrity. In E. coli, the DNA helicase UvrD is implicated in MMR, yet an analogous helicase activity has not been identified in eukaryotes. Here, we show that mammalian MCM9, a protein involved in replication and homologous recombination, forms a complex with MMR initiation proteins (MSH2, MSH3, MLH1, PMS1, and the clamp loader RFC) and is essential for MMR. Mcm9−/− cells display microsatellite instability and MMR deficiency. The MCM9 complex has a helicase activity that is required for efficient MMR since wild-type but not helicase-dead MCM9 restores MMR activity in Mcm9−/− cells. Moreover, MCM9 loading onto chromatin is MSH2-dependent, and in turn MCM9 stimulates the recruitment of MLH1 to chromatin. Our results reveal a role for MCM9 and its helicase activity in mammalian MMR

Proteomic data on the nuclear interactome of human MCM9

AbstractWe present data relating to the interactome of MCM9 from the nuclei of human cells. MCM9 belongs to the AAA+ superfamily, and contains an MCM domain and motifs that may confer DNA helicase activity. MCM9 has been shown to bind MCM8, and has been implicated in DNA replication and homologous recombination. However, the mechanistic basis of MCM9’s role in DNA repair is poorly understood, and proteins with which it interacts were hitherto unknown. We performed tandem affinity purification of MCM9 and its interacting proteins from nuclear extracts of human cells, followed by proteomic analysis, thereby generating a set of mass spectrometry data corresponding to the MCM9 interactome [1]. The proteomic data set comprises 29 mass spectrometry RAW files, deposited to the ProteomeXchange Consortium, and freely available from the PRIDE partner repository with the data set identifier http://www.ebi.ac.uk/pride/archive/projects/PXD000212. A set of 22 interacting proteins identified from the proteomic data was used to create an MCM9-centered interactive network diagram, using the Cytoscape program. These data allow the scientific community to access, mine and explore the human nuclear MCM9 interactome

Parkin Deficiency Delays Motor Decline and Disease Manifestation in a Mouse Model of Synucleinopathy

In synucleinopathies, including Parkinson's disease, partially ubiquitylated α-synuclein species phosphorylated on serine 129 (PS129-α-synuclein) accumulate abnormally. Parkin, an ubiquitin-protein ligase that is dysfunctional in autosomal recessive parkinsonism, protects against α-synuclein-mediated toxicity in various models

Cell-free DNA in Human Follicular Microenvironment: New Prognostic Biomarker to Predict in vitro Fertilization Outcomes

Article number: e0136172International audienceCell-free DNA (cfDNA) fragments, detected in blood and in other biological fluids, are released from apoptotic and/or necrotic cells. CfDNA is currently used as biomarker for the detection of many diseases such as some cancers and gynecological and obstetrics disorders. In this study, we investigated if cfDNA levels in follicular fluid (FF) samples from in vitro fertilization (IVF) patients, could be related to their ovarian reserve status, controlled ovarian stimulation (COS) protocols and IVF outcomes. Therefore, 117 FF samples were collected from women (n = 117) undergoing IVF/Intra-cytoplasmic sperm injection (ICSI) procedure and cfDNA concentration was quantified by ALU-quantitative PCR. We found that cfDNA level was significantly higher in FF samples from patients with ovarian reserve disorders (low functional ovarian reserve or polycystic ovary syndrome) than from patients with normal ovarian reserve (2.7 ± 2.7 ng/μl versus 1.7 ± 2.3 ng/μl, respectively, p = 0.03). Likewise, FF cfDNA levels were significant more elevated in women who received long ovarian stimulation (> 10 days) or high total dose of gonadotropins (≥ 3000 IU/l) than in women who received short stimulation duration (7-10 days) or total dose of gonadotropins < 3000 IU/l (2.4 ± 2.8 ng/μl versus 1.5 ± 1.9 ng/μl, p = 0.008; 2.2 ± 2.3 ng/μl versus 1.5 ± 2.1 ng/μl, p = 0.01, respectively). Finally, FF cfDNA level was an independent and significant predictive factor for pregnancy outcome (adjusted odds ratio = 0.69 [0.5; 0.96], p = 0.03). In multivariate analysis, the Receiving Operator Curve (ROC) analysis showed that the performance of FF cfDNA in predicting clinical pregnancy reached 0.73 [0.66-0.87] with 88% specificity and 60% sensitivity. CfDNA might constitute a promising biomarker of follicular micro-environment quality which could be used to predict IVF prognosis and to enhance female infertility management

Association between prenatal and perinatal factors and the severity of clinical presentation of children with ASD: Report from the ELENA COHORT

International audienceMany studies have suggested that prenatal and perinatal factors increase the risk for autism spectrum disorder (ASD). However, few reports have addressed the question of their influence on the severity of the clinical presentation of children with ASD. Our objective was to determine the prenatal and perinatal factors that are associated with the severity of autistic symptoms and intellectual and adaptive functioning deficits. Data were collected from a subset of 169 children with a confirmed diagnosis of ASD, recruited from the ELENA cohort. A risk of premature delivery was associated, with an increased risk for severe autistic symptoms and placental pathologies and birth complications were associated with an increased risk of communication adaptive deficits, in multivariate analysis. Our results highlight the importance of systematic screening for these pre/perinatal factors, especially in mothers at risk of having a child with ASD

Cell-free DNA level in follicular fluid pools according to the patients’ ovarian reserve status, ovarian reserve parameters and infertility length.

<p><b>A</b>, Follicular fluid cfDNA content in patients with normal ovarian reserve versus patients with ovarian reserve disorders (ovarian insufficiency and polycystic ovary syndrome); *p = 0.03. <b>B</b>, Follicular fluid cfDNA content according to the ovarian reserve parameters; left panel: AFC (<10 versus ≥ 10, *p = 0.04); right panel: AMH (≤ 1 versus > 1 ng/ml, *p = 0.06). <b>C</b>, Follicular fluid cfDNA levels according to the infertility length (1 versus ≥ 5 years, *p = 0.049).</p

CfDNA level in follicular fluid pools according to the embryo outcome at day 2 and 3.

<p><b>A</b>, Follicular Fluid cfDNA content according to the total number of embryos at day 2 (≤ 2 versus > 2, *p = 0.03). <b>B</b>, Follicular Fluid cfDNA content according to, left panel: the number of top quality (grade 1–2) embryos per patient (0 versus ≥ 1, *p = 0.002) at day 2, right panel: ratio between number of top quality embryos and total number of embryos (< 0.2 versus ≥ 0.2, *p = 0.04) at day 2. <b>C</b>, Follicular Fluid cfDNA content according to, left panel: number of top quality (grade 1–2) embryos per patient (0 versus ≥ 1, *p = 0.006) at day 3, right panel: ratio between number of top quality embryo and total number of embryos (< 0.2 versus ≥ 0.2, *p = 0.02) at day 3. <b>D</b>, Follicular Fluid cfDNA content according to, left panel: fragmentation rate at day 3 (<20% versus ≥ 20%, p = 0.18) and right panel: ratio between blastomere number and total embryo number at day 3 (<6 versus 6–8, *p = 0.02).</p