Left-right asymmetrical brain function underlies much of human cognition, behavior and emotion. Abnormalities of cerebral asymmetry are associated with schizophrenia and other neuropsychiatric disorders. The molecular, developmental and evolutionary origins of human brain asymmetry are unknown. We found significant association of a haplotype upstream of the gene LRRTM1 (Leucine-rich repeat transmembrane neuronal 1) with a quantitative measure of human handedness in a set of dyslexic siblings, when the haplotype was inherited paternally (P = 0.00002). While we were unable to find this effect in an epidemiological set of twin-based sibships, we did find that the same haplotype is overtransmitted paternally to individuals with schizophrenia/schizoaffective disorder in a study of 1002 affected families (P = 0.0014). We then found direct confirmatory evidence that LRRTM1 is an imprinted gene in humans that shows a variable pattern of maternal downregulation. We also showed that LRRTM1 is expressed during the development of specific forebrain structures, and thus could influence neuronal differentiation and connectivity. This is the first potential genetic influence on human handedness to be identified, and the first putative genetic effect on variability in human brain asymmetry. LRRTM1 is a candidate gene for involvement in several common neurodevelopmental disorders, and may have played a role in human cognitive and behavioral evolution.

ABSTRACT:The aim of the present study was to assess the contribution of polymorphisms in the breast cancer resistance protein/ATP-binding cassette transporter G2 (BCRP/ABCG2) gene to the placental expression from a new perspective, allelic imbalance. Polymorphisms were screened by polymerase chain reaction (PCR)-singlestrand conformation polymorphism analysis followed by sequencing with DNA extracted from 100 placentas. To evaluate whether the C421A polymorphism acts as a cis-element in BCRP transcription, allelic imbalance was determined using informative lymphoblasts and 56 samples of placental cDNA. In most of the placental samples we tested, the difference in expression levels between the two alleles was small, and only two samples indicated a monoallelic expression (i.e., preferential expression of one allele). These results suggest that 1) the predominant allelic expression pattern of BCRP in placental samples is biallelic, and 2) the mutation C421A is not a genetic variant acting in cis, but is considered to influence the translation efficiency.Breast cancer resistance protein (BCRP), also called mitoxantroneresistant protein, is the second member of the G family of ATPbinding cassette transporters (ABCG2) (Allikmets et al., 1998;Doyle et al., 1998;Miyake et al., 1999;Doyle and Ross, 2003). The BCRP gene is located at 4q22 and encodes a 72-kDa membrane protein composed of 655 amino acids (Allikmets et al., 1998;Doyle et al., 1998;Allen et al., 1999;Bailey-Dell et al., 2001). In contrast to many other ABC transporters, BCRP has only one ATP-binding region and one transmembrane domain. Therefore, BCRP is referred to as a half-transporter, and its homodimerization may be necessary to transport substrates .In normal human tissues, BCRP is highly expressed in the placenta, colon, small intestine, and liver (Maliepaard et al., 2001). On the basis of its tissue distribution and findings in knockout mice, BCRP is speculated to have a major influence on the pharmacokinetic and pharmacodynamic profiles of certain xenobiotics and endogenous substrates. For example, inhibition of mouse Bcrp 1 by GF120918, a dual inhibitor for BCRP and P-glycoprotein, has been demonstrated to increase the bioavailability of topotecan when GF120918 was administered orally to mdr1a/1b(Ϫ/Ϫ) mice (Jonker et al., 2000). In a clinical study, coadministration of GF120918 was also associated with a marked increase in the bioavailability of and systemic exposure to topotecan (Kruijtzer et al., 2002).Recent clinical studies indicate that the large interindividual variability in drug response occurs as a result of molecular alterations to various proteins such as drug-metabolizing enzymes, drug targets and receptors, and drug transporters. Most studies on molecular alterations have focused on the impact of single-nucleotide polymorphisms (SNPs) on the expression and function of these proteins (Evans and Relling, 1999;Evans and Johnson, 2001). Several groups have reported naturally occurring SNPs in the BCRP gene. G34A and C421A occur at relative...

We synthesized a galactose derivative, N-octyl-4-epi-␤-valienamine (NOEV), for a molecular therapy (chemical chaperone therapy) of a human neurogenetic disease, ␤-galactosidosis (GM1-gangliosidosis and Morquio B disease). It is a potent inhibitor of lysosomal ␤-galactosidase in vitro. Addition of NOEV in the culture medium restored mutant enzyme activity in cultured human or murine fibroblasts at low intracellular concentrations, resulting in a marked decrease of intracellular substrate storage. Short-term oral administration of NOEV to a model mouse of juvenile G M1-gangliosidosis, expressing a mutant enzyme protein R201C, resulted in significant enhancement of the enzyme activity in the brain and other tissues. Immunohistochemical stain revealed a decrease in the amount of G M1 and GA1 in neuronal cells in the fronto-temporal cerebral cortex and brainstem. However, mass biochemical analysis did not show the substrate reduction observed histochemically in these limited areas in the brain probably because of the brief duration of this investigation. Chemical chaperone therapy may be useful for certain patients with ␤-galactosidosis and potentially other lysosomal storage diseases with central nervous system involvement.

ObjectiveGaucher disease (GD) is a lysosomal storage disease characterized by a deficiency of glucocerebrosidase. Although enzyme‐replacement and substrate‐reduction therapies are available, their efficacies in treating the neurological manifestations of GD are negligible. Pharmacological chaperone therapy is hypothesized to offer a new strategy for treating the neurological manifestations of this disease. Specifically, ambroxol, a commonly used expectorant, has been proposed as a candidate pharmacological chaperone. The purpose of this study was to evaluate the safety, tolerability, and neurological efficacy of ambroxol in patients with neuronopathic GD.MethodsThis open‐label pilot study included five patients who received high‐dose oral ambroxol in combination with enzyme replacement therapy. Safety was assessed by adverse event query, physical examination, electrocardiography, laboratory studies, and drug concentration. Biochemical efficacy was assessed through evidence of glucocerebrosidase activity in the lymphocytes and glucosylsphingosine levels in the cerebrospinal fluid. Neurological efficacy was evaluated using the Unified Myoclonus Rating Scale, Gross Motor Function Measure, Functional Independence Measure, seizure frequency, pupillary light reflex, horizontal saccadic latency, and electrophysiologic studies.ResultsHigh‐dose oral ambroxol had good safety and tolerability, significantly increased lymphocyte glucocerebrosidase activity, permeated the blood–brain barrier, and decreased glucosylsphingosine levels in the cerebrospinal fluid. Myoclonus, seizures, and pupillary light reflex dysfunction markedly improved in all patients. Relief from myoclonus led to impressive recovery of gross motor function in two patients, allowing them to walk again.InterpretationPharmacological chaperone therapy with high‐dose oral ambroxol shows promise in treating neuronopathic GD, necessitating further clinical trials.

The production of cells capable of expressing gene(s) of interest is important for a variety of applications in biomedicine and biotechnology, including gene therapy and animal transgenesis. The ability to insert transgenes at a precise location in the genome, using site-specific recombinases such as Cre, FLP, and ΦC31, has major benefits for the efficiency of transgenesis. Recent work on integrases from ΦC31, R4, TP901-1 and Bxb1 phages demonstrated that these recombinases catalyze site-specific recombination in mammalian cells. In the present study, we examined the activities of integrases on site-specific recombination and gene expression in mammalian cells. We designed a human artificial chromosome (HAC) vector containing five recombination sites (ΦC31 attP, R4 attP, TP901-1 attP, Bxb1 attP and FRT; multi-integrase HAC vector) and de novo mammalian codon-optimized integrases. The multi-integrase HAC vector has several functions, including gene integration in a precise locus and avoiding genomic position effects; therefore, it was used as a platform to investigate integrase activities. Integrases carried out site-specific recombination at frequencies ranging from 39.3–96.8%. Additionally, we observed homogenous gene expression in 77.3–87.5% of colonies obtained using the multi-integrase HAC vector. This vector is also transferable to another cell line, and is capable of accepting genes of interest in this environment. These data suggest that integrases have high DNA recombination efficiencies in mammalian cells. The multi-integrase HAC vector enables us to produce transgene-expressing cells efficiently and create platform cell lines for gene expression.