The long non-coding RNA Gomafu is acutely regulated in response to neuronal activation and involved in schizophrenia-associated alternative splicing.

Schizophrenia (SZ) is a complex disease characterized by impaired neuronal functioning. Although defective alternative splicing has been linked to SZ, the molecular mechanisms responsible are unknown. Additionally, there is limited understanding of the early transcriptomic responses to neuronal activation. Here, we profile these transcriptomic responses and show that long non-coding RNAs (lncRNAs) are dynamically regulated by neuronal activation, including acute downregulation of the lncRNA Gomafu, previously implicated in brain and retinal development. Moreover, we demonstrate that Gomafu binds directly to the splicing factors QKI and SRSF1 (serine/arginine-rich splicing factor 1) and dysregulation of Gomafu leads to alternative splicing patterns that resemble those observed in SZ for the archetypal SZ-associated genes DISC1 and ERBB4. Finally, we show that Gomafu is downregulated in post-mortem cortical gray matter from the superior temporal gyrus in SZ. These results functionally link activity-regulated lncRNAs and alternative splicing in neuronal function and suggest that their dysregulation may contribute to neurological disorders.

TFII-I, a candidate gene for Williams syndrome cognitive profile: parallels between regional expression in mouse brain and human phenotype.

The gene for TFII-I, a widely expressed transcription factor, has been localized to an interval of human chromosome 7q11.23 that is commonly deleted in Williams syndrome (WS). The clinical phenotype of WS includes elfin facies, infantile hypercalcemia, supravalvular aortic stenosis, hyperacusis and mental retardation. The WS cognitive profile (WSCP) is notable for the differential impairment of visual-spatial abilities with relative sparing of verbal-linguistic function. Fine mapping of individuals with WS has revealed a close association between deletion of TFII-I and the WSCP. To determine the plausibility of the hypothesis that hemizygous deletion of TFII-I contributes to the WSCP, we have examined the anatomic distribution of TFII-I RNA and protein isoforms in brains from adult and embryonic mice. Our studies show that early in development, TFII-I expression is widespread and nearly uniform throughout the brain. In adult brain, TFII-I protein is present exclusively in neurons. Highest levels of expression are observed in cerebellar Purkinje cells and in hippocampal interneurons. TFII-I immunoreactivity is distinct from that of the related protein, TFII-IRD1, which is also localized to the region of human chromosome 7 deleted in WS. The expression pattern of TFII-I in mouse brain parallels regions in human brain which have been shown to be anatomically and functionally altered in humans with WS. These observations are consistent with the hypothesis that deletion of the gene for TFII-I contributes to the cognitive impairments observed in WS.

Identifying genes for neuron survival and axon outgrowth in Hirudo medicinalis.

We have studied the molecular basis of nervous system repair in invertebrate (Hirudo medicinalis) nerve cells. Unlike in mammals, neurons in invertebrates survive injury and regrow processes to restore the connections that they held before the damage occurred. To identify genes whose expression is regulated after injury, we have used subtractive probes, constructed from regenerating and non-regenerating ganglia from the leech Hirudo medicinalis, to screen cDNA libraries made from whole leech CNS or from identified microdissected neurons. We have identified genes of known or predicted function as well as novel genes. Known genes up-regulated within hours of injury and that are widely expressed in invertebrate and mammalian cells include thioredoxin and tubulin. Other known genes, e.g. Cysteine Rich Intestinal Protein (CRIP), have previously been identified in mammalian cells though not in regenerating adult neurons. Two regulated genes identified, myohemerythrin and the novel protein ReN3 are exclusively expressed in invertebrates. Thus our approach has enabled us to identify genes, present in a neuron of known function, that are up- and down-regulated within hours of axotomy, and that may underpin the intrinsic ability of invertebrate neurons to survive damage and initiate regrowth programmes.

HmCRIP, a cysteine-rich intestinal protein, is expressed by an identified regenerating nerve cell.

A Hirudo medicinalis cDNA isolated from regenerating CNS tissue at 24 h post-axotomy was identified as a leech homologue of the mammalian cysteine-rich intestinal proteins (CRIPs) and named HmCRIP. HmCRIP is up-regulated within 6 h of axotomy, peaking at 24 h. This is the first demonstration of a CRIP homologue in regenerating CNS and in a serotonergic neurone. In rodents CRIP is an important factor in the regulation of the inflammatory immune response through control of Th1/Th2 differentiation. The role of HmCRIP in the regeneration competent environment of the annelid central nervous system is discussed.

Poly(ADP-ribosyl)ation basally activated by DNA strand breaks reflects glutamate-nitric oxide neurotransmission.

Poly(ADP-ribose) polymerase (PARP) transfers ADP ribose groups from NAD(+) to nuclear proteins after activation by DNA strand breaks. PARP overactivation by massive DNA damage causes cell death via NAD(+) and ATP depletion. Heretofore, PARP has been thought to be inactive under basal physiologic conditions. We now report high basal levels of PARP activity and DNA strand breaks in discrete neuronal populations of the brain, in ventricular ependymal and subependymal cells and in peripheral tissues. In some peripheral tissues, such as skeletal muscle, spleen, heart, and kidney, PARP activity is reduced only partially in mice with PARP-1 gene deletion (PARP-1(-/-)), implicating activity of alternative forms of PARP. Glutamate neurotransmission involving N-methyl-d-aspartate (NMDA) receptors and neuronal nitric oxide synthase (nNOS) activity in part mediates neuronal DNA strand breaks and PARP activity, which are diminished by NMDA antagonists and NOS inhibitors and also diminished in mice with targeted deletion of nNOS gene (nNOS(-/-)). An increase in NAD(+) levels after treatment with NMDA antagonists or NOS inhibitors, as well as in nNOS(-/-) mice, indicates that basal glutamate-PARP activity regulates neuronal energy dynamics.

Pike. A nuclear gtpase that enhances PI3kinase activity and is regulated by protein 4.1N.

While cytoplasmic PI3Kinase (PI3K) is well characterized, regulation of nuclear PI3K has been obscure. A novel protein, PIKE (PI3Kinase Enhancer), interacts with nuclear PI3K to stimulate its lipid kinase activity. PIKE encodes a 753 amino acid nuclear GTPase. Dominant-negative PIKE prevents the NGF enhancement of PI3K and upregulation of cyclin D1. NGF treatment also leads to PIKE interactions with 4.1N, which has translocated to the nucleus, fitting with the initial identification of PIKE based on its binding 4.1N in a yeast two-hybrid screen. Overexpression of 4.1N abolishes PIKE effects on PI3K. Activation of nuclear PI3K by PIKE is inhibited by the NGF-stimulated 4.1N translocation to the nucleus. Thus, PIKE physiologically modulates the activation by NGF of nuclear PI3K.

Circadian rhythm of patched1 transcription in the pineal regulated by adrenergic stimulation and cAMP.

The tumor suppressor patched1 (PTC1), a product of the mammalian homologue of the Drosophila segment polarity gene patched, is a receptor for hedgehog (HH) and is crucial for embryonic development. Although little is known about the signal transduction pathways leading to the activation of ptc1, increased ptc1 transcription has always been associated with elevated HH activity and decreased activity of cAMP-dependent protein kinase A. Here, we demonstrate that in the mammalian pineal gland, ptc1 expression exhibits a dramatic diurnal rhythm with peak expression at midnight. ptc1 mRNA expression in the pineal is regulated by a clock mechanism mediated by the superior cervical ganglion. Most importantly, ptc1 transcription can be induced by agents activating the cAMP signal transduction pathway both in vivo and in vitro and appears to be independent of HH signaling.

Differential expression of putative transbilayer amphipath transporters.

The aminophospholipid translocase transports phosphatidylserine and phosphatidylethanolamine from one side of a bilayer to another. Cloning of the gene encoding the enzyme identified a new subfamily of P-type ATPases, proposed to be amphipath transporters. As reported here, mammals express as many as 17 different genes from this subfamily. Phylogenetic analysis reveals the genes to be grouped into several distinct classes and subclasses. To gain information on the functions represented by these groups, Northern analysis and in situ hybridization were used to examine the pattern of expression of a panel of subfamily members in the mouse. The genes are differentially expressed in the respiratory, digestive, and urogenital systems, endocrine organs, the eye, teeth, and thymus. With one exception, all of the genes are highly expressed in the central nervous system (CNS); however, the pattern of expression within the CNS differs substantially from gene to gene. These results suggest that the genes are expressed in a tissue-specific manner, are not simply redundant, and may represent isoforms that transport a variety of different amphipaths.

Neurobehavioral deficits in mice lacking the erythrocyte membrane cytoskeletal protein 4.1.

The erythrocyte membrane cytoskeletal protein 4.1 (4.1R) is a structural protein that confers stability and flexibility to erythrocytes via interactions with the cytoskeletal proteins spectrin and F-actin and with the band 3 and glycophorin C membrane proteins. Mutations in 4.1R can cause hereditary elliptocytosis, a disease characterized by a loss of the normal discoid morphology of erythrocytes, resulting in hemolytic anemia [1]. Different isoforms of the 4.1 protein have been identified in a wide variety of nonerythroid tissues by immunological methods [2-5]. The variation in molecular weight of these different 4.1 isoforms, which range from 30 to 210 kDa [6], has been attributed to complex alternative splicing of the 4.1R gene [7]. We recently identified two new 4.1 genes: one is generally expressed throughout the body (4. 1G) [8] and the other is expressed in central and peripheral neurons (4.1N) [9]. Here, we examined 4.1R expression by in situ hybridization analysis and found that 4.1R was selectively expressed in hematopoietic tissues and in specific neuronal populations. In the brain, high levels of 4.1R were discretely localized to granule cells in the cerebellum and dentate gyrus. We generated mice that lacked 4.1R expression; these mice had deficits in movement, coordination, balance and learning, in addition to the predicted hematological abnormalities. The neurobehavioral findings are consistent with the distribution of 4.1R in the brain, suggesting that 4.1R performs specific functions in the central nervous system.

Developmental expression pattern of phototransduction components in mammalian pineal implies a light-sensing function.

Whereas the pineal organs of lower vertebrates have been shown to be photosensitive, photic regulation of pineal function in adult mammals is thought be mediated entirely by retinal photoreceptors. Extraretinal regulation of pineal function has been reported in neonatal rodents, although both the site and molecular basis of extraretinal photoreception have remained obscure. In this study we examine the developmental expression pattern of all of the principal components of retinal phototransduction in rat pineal via cRNA in situ hybridization. All of the components needed to reconstitute a functional phototransduction pathway are expressed in the majority of neonatal pinealocytes, although the expression levels of many of these genes decline dramatically during development. These findings strongly support the theory that the neonatal rat pineal itself is photosensitive. In addition, we observe in neonatal pinealocytes the expression of both rod-specific and cone-specific phototransduction components, implying the existence of functionally different subtypes of pinealocytes that express varying combinations of phototransduction enzymes.

A case of atypical psychosis associated with alexithymia and a left fronto-temporal lesion: possible correlations.

The case history is presented of a man with an atypical psychosis and classical clinical features of alexithymia. On his last admission, the patient presented with starvation and hypernatremic coma. A CT scan, which was done because of the coma, revealed a large left fronto-temporal arachnoid cyst. The significance of this finding is reviewed in the light of previously suggested organic bases for alexithymia and related syndromes. Although the symptom of alexithymia is present, the patient's other symptoms do not fit readily into existing diagnostic categories and the resulting diagnostic dilemma is discussed.

Morphology and distribution of touch cell terminals in the skin of the leech.

1. The receptor terminals of individual mechanosensory neurones responding to light touch (T cells) have been visualized directly in the skin of the leech by injecting horseradish peroxidase (HRP) into their cell bodies in the central nervous system. The axons of injected cells could be followed from their origin in the neuropile of the ganglion to their terminals in the skin. 2. The axons of T cells run through ipsilateral nerve roots in the body wall to the base of the layer of epithelial cells in the skin. Here axons branch extensively and turn between the epithelial cells to end a few microns from the skin surface. These terminals are situated in intercellular spaces immediately below the junctional complex joining the outer ends of the epithelial cells. 3. The T cell terminals are free nerve endings with a beaded appearance; they contain large mitochondria and clusters of vesicles. 4. An individual T cell makes about 100 endings within a square millimetre of skin in the centre of its territory, and is estimated to make a total of several hundred endings. 5. The distribution of T cell endings observed directly agrees with physiological studies of receptive field organization and emphasizes the high degree of specificity of connexions of these neurones with their peripheral targets.