Dendritic and axonal morphology reflects the input and output of neurons and is a defining feature of neuronal types1,2, yet our knowledge of its diversity remains limited. Here, to systematically examine complete single-neuron morphologies on a brain-wide scale, we established a pipeline encompassing sparse labelling, whole-brain imaging, reconstruction, registration and analysis. We fully reconstructed 1,741 neurons from cortex, claustrum, thalamus, striatum and other brain regions in mice. We identified 11 major projection neuron types with distinct morphological features and corresponding transcriptomic identities. Extensive projectional diversity was found within each of these major types, on the basis of which some types were clustered into more refined subtypes. This diversity follows a set of generalizable principles that govern long-range axonal projections at different levels, including molecular correspondence, divergent or convergent projection, axon termination pattern, regional specificity, topography, and individual cell variability. Although clear concordance with transcriptomic profiles is evident at the level of major projection type, fine-grained morphological diversity often does not readily correlate with transcriptomic subtypes derived from unsupervised clustering, highlighting the need for single-cell cross-modality studies. Overall, our study demonstrates the crucial need for quantitative description of complete single-cell anatomy in cell-type classification, as single-cell morphological diversity reveals a plethora of ways in which different cell types and their individual members may contribute to the configuration and function of their respective circuits.

IPD patients have a higher prevalence of PN than controls. Although causality is not established, levodopa exposure is associated with MMA elevation and sensorimotor neuropathy in IPD patients. Cobalamin replacement concurrent with levodopa therapy should be considered to protect against development of PN in IPD patients.

To develop an ideal blood clot imaging and targeting agent, a single-chain antibody (SCA) fragment based on a fibrin-specific monoclonal antibody, MH-1, was constructed and produced via secretion from Bacillus subtilis. Through a systematic study involving a series of B. subtilis strains, insufficient intracellular and extracytoplasmic molecular chaperones and high sensitivity to wall-bound protease (WprA) were believed to be the major factors that lead to poor production of MH-1 SCA. Intracellular and extracytoplasmic molecular chaperones apparently act in a sequential manner. The combination of enhanced coproduction of both molecular chaperones and wprA inactivation leads to the development of an engineered B. subtilis strain, WB800HM[pEPP]. This strain allows secretory production of MH-1 SCA at a level of 10 to 15 mg/liter. In contrast, with WB700N (a seven-extracellular-protease-deficient strain) as the host, no MH-1 SCA could be detected in both secreted and cellular fractions. Secreted MH-1 SCA from WB800HM[pMH1, pEPP] could be affinity purified using a protein L matrix. It retains comparable affinity and specificity as the parental MH-1 monoclonal antibody. This expression system can potentially be applied to produce other single-chain antibody fragments, especially those with folding and protease sensitivity problems.

Since the downregulation of I(tof) was observed with overexpression of calcineurin and was also reversed by the calcineurin inhibitor CsA, we conclude that downregulation of I(tof) is a consequence of calcineurin overexpression.

32Ever since the seminal findings of Ramon y Cajal, dendritic and axonal morphology has been 33 recognized as a defining feature of neuronal types and their connectivity. Yet our knowledge 34 about the diversity of neuronal morphology, in particular its distant axonal projections, is still 35 extremely limited. To systematically obtain single neuron full morphology on a brain-wide scale 36in mice, we established a pipeline that encompasses five major components: sparse labeling, 37whole-brain imaging, reconstruction, registration, and classification. We achieved sparse, robust 38and consistent fluorescent labeling of a wide range of neuronal types across the mouse brain in 39 an efficient way by combining transgenic or viral Cre delivery with novel transgenic reporter 40 lines, and generated a large set of high-resolution whole-brain fluorescent imaging datasets 41containing thousands of reconstructable neurons using the fluorescence micro-optical sectioning 42 tomography (fMOST) system. We developed a set of software tools based on the visualization 43 and analysis suite, Vaa3D, for large-volume image data processing and computation-assisted 44 morphological reconstruction. In a proof-of-principle case, we reconstructed full morphologies 45 of 96 neurons from the claustrum and cortex that belong to a single transcriptomically-defined 46 neuronal subclass. We developed a data-driven clustering approach to classify them into multiple 47 morphological and projection types, suggesting that these neurons work in a targeted and 48coordinated manner to process cortical information. Imaging data and the new computational 49 reconstruction tools are publicly available to enable community-based efforts towards large-scale 50 full morphology reconstruction of neurons throughout the entire mouse brain. 51 52 53

Abstract-The N629D mutation, adjacent to the GFG signature sequence of the HERG1 A K ϩ channel, causes long-QT syndrome (LQTS). Expression of N629D in Xenopus oocytes produces a rapidly activating, noninactivating current. N629D is nonselective among monovalent cations; permeation of K ϩ was similar to that of Na ϩ or Cs ϩ . During repolarization to potentials between Ϫ30 and Ϫ70 mV, N629D manifested an inward tail current, which was abolished by replacement of extracellular Na ϩ (Na ϩ e ) with extracellular N-methyl-D-glucamine (NMG e ). Because LQTS occurs in heterozygous patients, we coexpressed N629D and wild type (WT) at equimolar concentrations. Heteromultimer formation was demonstrated by analyzing the response to 0 [K ϩ ] e . The outward time-dependent current was nearly eliminated for WT at 0 [K ϩ ] e , whereas no reduction was observed for homomultimeric N629D or for the equimolar coexpressed current. To assess physiological significance, dofetilide-sensitive currents were recorded during application of simulated action potential clamps. During phase 3 repolarization, WT manifested outward currents, whereas homomultimeric N629D manifested inward depolarizing currents. During coexpression studies, variable phenotypes were observed ranging from a reduction in outward repolarizing current to net inward depolarizing current during phase 3. In summary, N629D replaces the WT outward repolarizing tail current with an inward depolarizing sodium current, which is expected to delay later stages of repolarization and contribute to arrhythmogenesis. Thus, the consequences of N629D resemble the pathophysiology seen in LQT3 Na ϩ channel mutations and may be considered the first LQTS K Key Words: long-QT syndrome Ⅲ HERG1 Ⅲ K ϩ channel Ⅲ gain of function F amilial long-QT syndrome (LQTS) results from defects in sodium and potassium ion channels that cause prolongation of cardiac repolarization and arrhythmias. 1 LQT2 is associated with mutations of the human ether-a-go-go-related gene, HERG1. [2][3][4][5][6][7][8][9][10] The HERG1 primary transcript is alternatively processed, giving rise to at least 3 functional mRNAs, HERG1 A, HERG1 AЈ, and HERG1 B, encoding proteins with distinct physiological properties. 11,12 There are several mechanisms by which individual mutations in HERG1 produce LQTS. 5-9 Some exert a dominant phenotype through loss of repolarizing current. These include mutations that either cause defects in intracellular transport or result in channels that do not open. Alternatively, V630L forms heterotetramers with wild type (WT) that have reduced open probability due to a negative shift in voltage dependence of inactivation. Abnormally fast deactivation mutations caused by mutations in the N terminus of HERG1 A result in reduction of outward current during phase 3 repolarization and thus LQTS. 10 The recently described N629D mutation 9 is of particular interest, as it alters the pore selectivity signature sequence from GFGN to GFGD. 13 In most K ϩ channels, including the extensively studied Shaker chann...

Ever since the seminal findings of Ramon y Cajal, dendritic and axonal morphology has been recognized as a defining feature of neuronal types. Yet our knowledge concerning the diversity of neuronal morphologies, in particular distal axonal projection patterns, is extremely limited. To systematically obtain single neuron full morphology on a brain-wide scale, we established a platform with five major components: sparse labeling, whole-brain imaging, reconstruction, registration, and classification. We achieved sparse, robust and consistent fluorescent labeling of a wide range of neuronal types by combining transgenic or viral Cre delivery with novel transgenic reporter lines. We acquired high-resolution whole-brain fluorescent images from a large set of sparsely labeled brains using fluorescence micro-optical sectioning tomography (fMOST). We developed a set of software tools for efficient large-volume image data processing, registration to the Allen Mouse Brain Common Coordinate Framework (CCF), and computer-assisted morphological reconstruction. We reconstructed and analyzed the complete morphologies of 1,708 neurons from the striatum, thalamus, cortex and claustrum. Finally, we classified these cells into multiple morphological and projection types and identified a set of region-specific organizational rules of long-range axonal projections at the single cell level. Specifically, different neuron types from different regions follow highly distinct rules in convergent or divergent projection, feedforward or feedback axon termination patterns, and between-cell homogeneity or heterogeneity. Major molecularly defined classes or types of neurons have correspondingly distinct morphological and projection patterns, however, we also identify further remarkably extensive morphological and projection diversity at more fine-grained levels within the major types that cannot presently be accounted for by preexisting transcriptomic subtypes. These insights reinforce the importance of full morphological characterization of brain cell types and suggest a plethora of ways different cell types and individual neurons may contribute to the function of their respective circuits.

This study reports a novel therapeutic strategy and mechanism to partially restore physiologic function in this HERG LQTS mutation.