The human Pur factor binds strongly to a sequence element repeated within zones of initiation of DNA replication in several eukaryotic cells.

No abstract

Congenital cataracts (CCs), responsible for about one-third of blindness in infants, are a major cause of vision loss in children worldwide. Autosomal-recessive congenital cataracts (arCC) form a clinically diverse and genetically heterogeneous group of disorders of the crystalline lens. To identify the genetic cause of arCC in consanguineous Pakistani families, we performed genome-wide linkage analysis and fine mapping and identified linkage to 3p21-p22 with a summed LOD score of 33.42. Mutations in the gene encoding FYVE and coiled-coil domain containing 1 (FYCO1), a PI(3)P-binding protein family member that is associated with the exterior of autophagosomes and mediates microtubule plus-end-directed vesicle transport, were identified in 12 Pakistani families and one Arab Israeli family in which arCC had previously been mapped to the overlapping CATC2 region. Nine different mutations were identified, including c.3755 delC (p.Ala1252AspfsX71), c.3858_3862dupGGAAT (p.Leu1288TrpfsX37), c.1045 C>T (p.Gln349X), c.2206C>T (p.Gln736X), c.2761C>T (p.Arg921X), c.2830C>T (p.Arg944X), c.3150+1 G>T, c.4127T>C (p.Leu1376Pro), and c.1546C>T (p.Gln516X). Fyco1 is expressed in the mouse embryonic and adult lens and peaks at P12d. Expressed mutant proteins p.Leu1288TrpfsX37 and p.Gln736X are truncated on immunoblots. Wild-type and p.L1376P FYCO1, the only missense mutant identified, migrate at the expected molecular mass. Both wild-type and p. Leu1376Pro FYCO1 proteins expressed in human lens epithelial cells partially colocalize to microtubules and are found adjacent to Golgi, but they primarily colocalize to autophagosomes. Thus, FYCO1 is involved in lens development and transparency in humans, and mutations in this gene are one of the most common causes of arCC in the Pakistani population.

Connectivity-based parcellation approaches present an innovative method to segregate the brain into functionally specialized regions. These approaches have significantly advanced our understanding of the human brain organization. However, parallel progress in animal research is sparse. Using resting-state fMRI data and a novel, data-driven parcellation method, we have obtained robust functional parcellations of the rat brain. These functional parcellations reveal the regional specialization of the rat brain, which exhibited high within-parcel homogeneity and high reproducibility across animals. Graph analysis of the whole-brain network constructed based on these functional parcels indicates that the rat brain has a topological organization similar to humans, characterized by both segregation and integration. Our study also provides compelling evidence that the cingulate cortex is a functional hub region conserved from rodents to humans. Together, this study has characterized the rat brain specialization and integration, and has significantly advanced our understanding of the rat brain organization. In addition, it is valuable for studies of comparative functional neuroanatomy in mammalian brains.

Hyperhomocysteinemia (Hhcy) may induce memory deficits with b-amyloid (Ab) accumulation and tau hyperphosphorylation. Simultaneous supplement of folate and vitamin B12 partially restored the plasma homocysteine level and attenuated tau hyperphosphorylation, Ab accumulation and memory impairments induced by Hhcy. However, folate and vitamin B12 treatment have no effects on Hhcy which has the methylenetetrahydrofolate reductase genotype mutation. In this study, we investigated the effects of simultaneous supplement of betaine on Alzheimer-like pathological changes and memory deficits in hyperhomocysteinemic rats after a 2-week induction by vena caudalis injection of homocysteine (Hcy). We found that supplementation of betaine could ameliorate the Hcy-induced memory deficits, enhance longterm potentiation (LTP) and increase dendritic branches numbers and the density of the dendritic spines, with upregulation of NR1, NR2A, synaptotagmin, synaptophysin, and phosphorylated synapsin I protein levels. Supplementation of betaine also attenuated the Hcy-induced tau hyperphosphorylation at multiple AD-related sites through activation protein phosphatase-2A (PP2A) with decreased inhibitory demethylated PP2A C at Leu309 and phosphorylated PP2A C at Tyr307. In addition, supplementation of betaine also decreased Ab production with decreased presenilin-1 protein levels. Our data suggest that betaine could be a promising candidate for arresting Hcy-induced AD-like pathological changes and memory deficits.

Alterations in resting-state networks (RSNs) are often associated with psychiatric and neurologic disorders. Given this critical linkage, it has been hypothesized that RSNs can potentially be used as endophenotypes for brain diseases. To validate this notion, a critical step is to show that RSNs exhibit heritability. However, the investigation of the genetic basis of RSNs has only been attempted in the default-mode network at the region-of-interest level, while the genetic control on other RSNs has not been determined yet. Here we examined the genetic and environmental influences on eight well-characterized RSNs by using a twin design. Resting-state functional magnetic resonance imaging data in 56 pairs of twins were collected. The genetic and environmental effects on each RSN were estimated by fitting the functional connectivity covariance of each voxel in the RSN to the classic ACE twin model. The data showed that although environmental effects accounted for the majority of variance in widespread areas, there were specific brain sites that showed significant genetic control for individual RSNs. These results suggest that part of the human brain functional connectome is shaped by genomic constraints. Importantly, this information can be useful for bridging genetic analysis and network-level assessment of brain disorders.

Rodent models are essential to translational research in health and disease. Investigation in rodent brain function and organization at the systems level using resting-state functional magnetic resonance imaging (rsfMRI) has become increasingly popular. Due to this rapid progress, publicly shared rodent rsfMRI databases can be of particular interest and importance to the scientific community, as inspired by human neuroscience and psychiatric research that are substantially facilitated by open human neuroimaging datasets. However, such databases in rats are still rare. In this paper, we share an open rsfMRI database acquired in 90 rats with a well-established awake imaging paradigm that avoids anesthesia interference. Both raw and preprocessed data are made publicly available. Procedures in data preprocessing to remove artefacts induced by the scanner, head motion and non-neural physiological noise are described in details. We also showcase inter-regional functional connectivity and functional networks obtained from the database.

γS-Crystallin, important in maintaining lens transparency, is a monomeric βγ-crystallin comprising two paired homologous domains, each with two Greek key motifs. An autosomal dominant cortical progressive cataract has been associated with a G18V mutation in human γS-crystallin. To investigate the molecular mechanism of this cataract and confirm the causative nature of the G18V mutation we examined resultant changes in conformation and stability. Human γS-crystallin cDNA was cloned into pET-20b(+) and the G18V mutant was generated by site-directed mutagenesis. Recombinant HγS-crystallins were expressed in E. coli and purified by ion-exchange and size-exclusion chromatography. By analytical ultracentrifugation wild type and mutant HγS-crystallin are monomers of about 21.95±0.21kDa and 20.89 ± 0.18kDa respectively and have similar secondary structures by far-UV CD. In increasing levels of guanidinium hydrochloride (GuHCl), a sharp red shift in fluorescence λmax and increase in emission correlating with exposure of tryptophans to the protein surface is detected earlier in the mutant protein. Under thermal stress, the G18V mutant begins to show changes in tryptophan fluorescence above 42°C and shows a Tm of 65°C as monitored by CD at 218 nm, while wild type HγS-crystallin is very stable with Tm values of 75.5°C and 75.0°C as measured by fluorescence and CD respectively. Equilibrium unfolding/refolding experiments as a function of GuHCl confirm the relative instability of the G18V mutant. Wild type HγS-crystallin exhibits a two-state transition and reversible refolding above 1.0M GuHCl, but the unfolding transition of mutant HγS-crystallin shows an intermediate state. The first transition (N→I) shows a [GuHCl]1/2 of 0.5 M while the second transition (I→U) has the same [GuHCl]1/2 as wild type HγS-crystallin, about 2.0 M. Our present study confirms the high stability of wild type HγS-crystallin and demonstrates that the G18V mutation destabilizes the protein towards heat and GuHCl induced unfolding. These biophysical characteristics are consistent with the progressive cataract formation seen in the family members carrying this mutation.