The rockefeller university

The 11-subunit eukaryotic replicative helicase CMG (Cdc45, Mcm2-7, GINS) tightly binds Mcm10, an essential replication protein in all eukaryotes. Here we show that Mcm10 has a potent strand-annealing activity both alone and in complex with CMG. CMG-Mcm10 unwinds and then reanneals single strands soon after they have been unwound in vitro. Given the DNA damage and replisome instability associated with loss of Mcm10 function, we examined the effect of Mcm10 on fork regression. Fork regression requires the unwinding and pairing of newly synthesized strands, performed by a specialized class of ATP-dependent DNA translocases. We show here that Mcm10 inhibits fork regression by the well-known fork reversal enzyme SMARCAL1. We propose that Mcm10 inhibits the unwinding of nascent strands to prevent fork regression at normal unperturbed replication forks, either by binding the fork junction to form a block to SMARCAL1 or by reannealing unwound nascent strands to their parental template. Analysis of the CMG-Mcm10 complex by cross-linking mass spectrometry reveals Mcm10 interacts with six CMG subunits, with the DNA-binding region of Mcm10 on the N-face of CMG. This position on CMG places Mcm10 at the fork junction, consistent with a role in regulating fork regression.

Nephronophthisis-related ciliopathies (NPHP-RCs) are a group of inherited diseases that are associated with defects in primary cilium structure and function. To identify genes mutated in NPHP-RC, we performed homozygosity mapping and whole-exome sequencing for >100 individuals, some of whom were single affected individuals born to consanguineous parents and some of whom were siblings of indexes who were also affected by NPHP-RC. We then performed high-throughput exon sequencing in a worldwide cohort of 800 additional families affected by NPHP-RC. We identified two ADAMTS9 mutations (c.4575_4576de1 [p.Gln1525Hisfs*60] and c.194C>G [p.Thr65Arg]) that appear to cause NPHP-RC. Although ADAMTS9 is known to be a secreted extracellular metalloproteinase, we found that ADAMTS9 localized near the basal bodies of primary cilia in the cytoplasm. Heterologously expressed wild-type ADAMTS9, in contrast to mutant proteins detected in individuals with NPHP-RC, localized to the vicinity of the basal body. Loss of ADAMTS9 resulted in shortened cilia and defective sonic hedgehog signaling. Knockout of Adamts9 in IMCD3 cells, followed by spheroid induction, resulted in defective lumen formation, which was rescued by an overexpression of wild-type, but not of mutant, ADAMTS9. Knockdown of adamts9 in zebrafish recapitulated NPHP-RC phenotypes, including renal cysts and hydrocephalus. These findings suggest that the identified mutations in ADAMTS9 cause NPHP-RC and that ADAMTS9 is required for the formation and function of primary cilia.

Structures of the cannabinoid receptor 1 (CB1) in complex with an "ultrapotent'' synthetic cannabinoid and its G protein (Krishna Kumar et al., 2019) and CB2 in complex with a new rationally designed inverse agonist (Li et al., 2019) provide unique snapshots of the molecular pharmacology of cannabinoids.

There is a growing appreciation for the importance of the gut microbiota as a therapeutic target in various diseases. However, there are only a handful of known commensal strains that can potentially be used to manipulate host physiological functions. Here we isolate a consortium of 11 bacterial strains from healthy human donor faeces that is capable of robustly inducing interferon-gamma-producing CD8 T cells in the intestine. These 11 strains act together to mediate the induction without causing inflammation in a manner that is dependent on CD103(+) dendritic cells and major histocompatibility (MHC) class Ia molecules. Colonization of mice with the 11-strain mixture enhances both host resistance against Listeria monocytogenes infection and the therapeutic efficacy of immune checkpoint inhibitors in syngeneic tumour models. The 11 strains primarily represent rare, low-abundance components of the human microbiome, and thus have great potential as broadly effective biotherapeutics.

Dysplastic naevi (DN) are benign lesions with atypical features intermediate between that of common melanocytic naevi (CMN) and malignant melanoma (MM). Debate remains over whether DN represent progressive lesions from CMN. Through gene expression profiling and analysis of molecular gene signatures, our study revealed progressive increases in immune activation and regulation, along with pathways implicated in melanomagenesis, from CMN to DN to MM. Using criteria of 1.5-fold change and false discovery rate <= 0.05, we found differential expression of 7186 probes (6370 unique genes) with the largest difference detected between DN and MM from the standpoint of genomic melanoma progression. Despite progressive increases in the T-helper type 1 (Th1)-inducing gene (IL-12), RT-PCR indicated impaired Th1 or cytotoxic T-cell response (decreased IFN-gamma) in MM. Concordantly, our results indicated progressive increases in molecular markers associated with regulatory T cells, exhausted T cells and tolerogenic dendritic cells, including detection of increased expression of suppressor of cytokine signalling 3 (SOCS3) in dendritic cells associated with MM. All together, our findings suggest that the increased immunosuppressive microenvironment of melanoma may contribute to unhampered proliferation of neoplastic cells. In addition, the detection of increased markers associated with tolerogenic dendritic cells in MM suggests that targeting these suppressive immune cell types may represent an alternative avenue for future immunotherapy.

The newly released IEEE Std C95.1 (TM)-2019 defines exposure criteria and associated limits for the protection of persons against established adverse health effects from exposures to electric, magnetic, and electromagnetic fields, in the frequency range 0 Hz to 300 GHz. The exposure limits apply to persons permitted in restricted environments and to the general public in unrestricted environments. These limits are not intended to apply to the exposure of patients by or under the direction of physicians and care professionals, as well as to the exposure of informed volunteers in scientific research studies, or to the use of medical devices or implants. IEEE Std C95.1 (TM)-2019 can be obtained at no cost from the IEEE Get Program https://ieeexplore.ieee.org/document/8859679.

Age and estrogens may impact the mobility of N-methyl-D-aspartate receptors (NMDARs) in hippocampal synapses. Here, we used serial section immunogold electron microscopy to examine whether phosphorylated tyrosine 1472 NR2B (pY1472), which is involved in the surface expression of NMDARs, is altered in the dorsal hippocampus of young (3-4 months old) and aged ( similar to 24 months old) ovariectomized rats treated with 17 beta-estradiol or vehicle for 2 days. The number of gold particles labeling pY1472 was higher in presynaptic and postsynaptic compartments of aged rats with low estradiol (vehicle-treated) compared to other groups. In terminals, pY1472 levels were elevated in aged rats but reduced by estradiol treatment to levels seen in young rats. Conversely, the mitochondria number was lower in aged females but was restored to young levels by estradiol. In the postsynaptic density and dendritic spines, estradiol reduced pY1472 in young and aged rats. As phosphorylation at Y1472 blocks NR2B endocytosis, reduction of pY1472 by estradiol suggests another mechanism through which estrogen enhances synaptic plasticity by altering localization of NMDAR subunits within synapses. (C) 2018 Elsevier Inc. All rights reserved.

The AML1-ETO fusion protein, generated by the t(8;21) chromosomal translocation, is causally involved in nearly 20% of acute myeloid leukemia (AML) cases. In leukemic cells, AML1-ETO resides in and functions through a stable protein complex, AML1-ETO-containing transcription factor complex (AETFC), that contains multiple transcription (co)factors. Among these AETFC components, HEB and E2A, two members of the ubiquitously expressed E proteins, directly interact with AML1-ETO, confer new DNA-binding capacity to AETFC, and are essential for leukemogenesis. However, the third E protein, E2-2, is specifically silenced in AML1-ETO-expressing leukemic cells, suggesting E2-2 as a negative factor of leukemogenesis. Indeed, ectopic expression of E2-2 selectively inhibits the growth of AML1-ETO-expressing leukemic cells, and this inhibition requires the bHLH DNA-binding domain. RNA-seq and ChIP-seq analyses reveal that, despite some overlap, the three E proteins differentially regulate many target genes. In particular, studies show that E2-2 both redistributes AETFC to, and activates, some genes associated with dendritic cell differentiation and represses MYC target genes. In AML patients, the expression of E2-2 is relatively lower in the t(8; 21) subtype, and an E2-2 target gene, THPO, is identified as a potential predictor of relapse. In a mouse model of human t(8; 21) leukemia, E2-2 suppression accelerates leukemogenesis. Taken together, these results reveal that, in contrast to HEB and E2A, which facilitate AML1-ETO-mediated leukemogenesis, E2-2 compromises the function of AETFC and negatively regulates leukemogenesis. The three E proteins thus define a heterogeneity of AETFC, which improves our understanding of the precise mechanism of leukemogenesis and assists development of diagnostic/therapeutic strategies.

Mitochondria are metabolic organelles that are essential for mammalian life, but the dynamics of mitochondrial metabolism within mammalian tissues in vivo remains incompletely understood. While whole-tissue metabolite profiling has been useful for studying metabolism in vivo, such an approach lacks resolution at the cellular and subcellular level. In vivo methods for interrogating organellar metabolites in specific cell types within mammalian tissues have been limited. To address this, we built on prior work in which we exploited a mitochondrially localized 3XHA epitope tag (MITO-Tag) for the fast isolation of mitochondria from cultured cells to generate MITO-Tag Mice. Affording spatiotemporal control over MITO-Tag expression, these transgenic animals enable the rapid, cell-type-specific immunoisolation of mitochondria from tissues, which we verified using a combination of proteomic and metabolomic approaches. Using MITOTag Mice and targeted and untargeted metabolite profiling, we identified changes during fasted and refed conditions in a diverse array of mitochondrial metabolites in hepatocytes and found metabolites that behaved differently at the mitochondrial versus wholetissue level. MITO-Tag Mice should have utility for studying mitochondrial physiology, and our strategy should be generally applicable for studying other mammalian organelles in specific cell types in vivo.

Conditional knockout (KO) mouse models are invaluable for elucidating the physiological roles of platelets. The Platelet factor 4-Cre recombinase (Pf4-Cre) transgenic mouse is the current model of choice for generating megakaryocyte/platelet-specific KO mice. Platelets and leukocytes work closely together in a wide range of disease settings, yet the specific contribution of platelets to these processes remains unclear. This is partially a result of the Pf4-Cre transgene being expressed in a variety of leukocyte populations. To overcome this issue, we developed a Gp1ba-Cre transgenic mouse strain in which Cre expression is driven by the endogenous Gp1ba locus. By crossing Gp1ba-Cre and Pf4-Cre mice to the mT/mG dual-fluorescence reporter mouse and performing a head-to-head comparison, we demonstrate more stringent megakaryocyte lineage-specific expression of the Gp1ba-Cre transgene. Broader tissue expression was observed with the Pf4-Cre transgene, leading to recombination in many hematopoietic lineages, including monocytes, macrophages, granulocytes, and dendritic and B and T cells. Direct comparison of phenotypes of Csk, Shp1, or CD148 conditional KO mice generated using either the Gp1ba-Cre or Pf4-Cre strains revealed similar platelet phenotypes. However, additional inflammatory and immunological anomalies were observed in Pf4-Cre-generated KO mice as a result of nonspecific deletion in other hematopoietic lineages. By excluding leukocyte contributions to phenotypes, the Gp1ba-Cre mousewill advance our understanding of the role of platelets in inflammation and other pathophysiological processes in which platelet-leukocyte interactions are involved.