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Adenosine receptors (ARs) belong to the family of G protein-coupled receptors. Four distinct subtypes are known, termed adenosine A 1 , A 2A , A 2B and A 3 . receptors and they are regulated by adenosine which is one of the most ancient and widespread chemical messengers in the animal and plant kingdoms. Moreover, ARs are widely distributed in human body and they are expressed with different density in diverse tissues. It is not surprising that they are involved in the regulation of several physiopathological processes. Adenosiland represents the first tentative of an integrated bioinformatics and chemoinformatics web-resource dedicated to adenosine receptors. This informatics platform provides a wide-ranging of structure based and ligand based query functions to facilitate the exploration of adenosine receptor structures from primary sequences to three-dimensional architectures. Here, we present an overview of Adenosiland platform describing the most valuable searching tools and their functionalities. Adenosiland can be freely accessed at http://mms.dsfarm.unipd.it/Adenosiland/ .

Since the discovery of radial glia as the source of neurons, their heterogeneity in regard to neurogenesis has been described by clonal and time-lapse analysis in vitro. However, the molecular determinants specifying neurogenic radial glia differently from radial glia that mostly self-renew remain ill-defined. Here, we isolated two radial glial subsets that co-exist at mid-neurogenesis in the developing cerebral cortex and their immediate progeny. While one subset generates neurons directly, the other is largely non-neurogenic but also gives rise to Tbr2-positive basal precursors, thereby contributing indirectly to neurogenesis. Isolation of these distinct radial glia subtypes allowed determining interesting differences in their transcriptome. These transcriptomes were also strikingly different from the transcriptome of radial glia isolated at the end of neurogenesis. This analysis therefore identifies, for the first time, the lineage origin of basal progenitors and the molecular differences of this lineage in comparison to directly neurogenic and gliogenic radial glia.

We report the cloning of a novel mouse gene (Pcp4l1) that encodes a polypeptide with significant sequence similarity to the Purkinje cell protein 4 gene (Pcp4) and describe its expression pattern during mouse development. Similar to Pcp4, the Pc4l1 gene product is characterized by the presence of an IQ domain and is highly conserved across evolution. RNA in situ hybridization reveals instead that Pcp4l1 has a distinct pattern of expression: it is only expressed in the central nervous system (CNS), and is first detected at E9.5 in the mesencephalic and metencephalic roof plate as well as in the isthmus, in a region that overlaps the expression domains of Pax2, Fgf8 and Wnt1. Thus, the early Pcp4l1 expression pattern coincides with the regional expression of well-characterized patterning molecules in the organizing centers of the developing brain. Starting at midgestation, Pcp4l1 is mainly expressed in the structures of the circumventricular organs, including the subcommissural organ, the rhombencephalic and telencephalic choroid plexi, and the pineal gland. In the adult brain, this transcript is also detected in laminar as well as in several nuclear structures of the CNS., This work was supported by the Italian Telethon Foundation, by the European Community (grant nr. QLRT-1999-00793) and by the Fondazione Agarini.

A novel type of DNA-binding domain, the ‘T-box’ domain, characterizes an increasingly large family of transcription factors (Trends Genet. 15 (1999) 154). We have identified and characterized the expression pattern of a new member of the Tbr1 subfamily of T-box genes; this gene has been recently named T-bet/Tbx21 (Genomics 70 (2000) 41; Cell 17 (2000) 655; Science 292 (2001) 1907; Science 295 (2002) 338). The sequence and expression of Tbr1 and eomesodermin/Tbr2 are closely related to T-bet/Tbx21. The expression of Tbr1 (Neuron 15 (1995) 63) and Tbr2 (Mech Dev 84 (1999) 133) have virtually identical onset, at around E10.5, and expression domains in the mouse telencephalon. While Tbr1 is expressed in postmitotic neurons, Tbr2 (which is also expressed during gastrulation is also expressed in neural progenitors. We have used in situ hybridization to determine the temporal and spatial distribution of T-bet/Tbx21 expression during mouse development. T-bet/Tbx21 expression is exclusively restricted to the olfactory bulb and the thymus. To assess the distribution of T-BET/TBX21 expression in the haematopoietic compartment we used reverse transcriptase-polymerase chain reaction and found its expression in several human blood cell lineages, including progenitors/stem cells, immature B cells and peripheral T cells.

Oral-facial-digital type 1 syndrome (OFD1 [MIM 311200]) is transmitted as an X-linked dominant condition with lethality in males and is characterized by malformations of the face, oral cavity, and digits, and by a highly variable expressivity even within the same family. Malformation of the brain and polycystic kidneys are commonly associated with this disorder. The locus for OFD1 was mapped by linkage analysis to a 12-Mb interval, flanked by markers DXS85 and DXS7105 in the Xp22 region. To identify the gene responsible for this syndrome, we analyzed several transcripts mapping to the region and found mutations in OFD1 (formerly named "Cxorf5/71-7a"), encoding a protein containing coiled-coil alpha-helical domains. Seven patients with OFD1, including three with familial and four with sporadic cases, were analyzed. Analysis of the familial cases revealed a missense mutation, a 19-bp deletion, and a single base-pair deletion leading to a frameshift. In the sporadic cases, we found a missense (de novo), a nonsense, a splice, and a frameshift mutation. RNA in situ studies on mouse embryo tissue sections show that Ofd1 is developmentally regulated and is expressed in all tissues affected in OFD1 syndrome. The involvement of OFD1 in oral-facial-digital type I syndrome demonstrates an important role of this gene in human development.

During corticogenesis, early-born neurons of the preplate and layer 6 are important for guiding subsequent neuronal migrations and axonal projections. Tbr1 is a putative transcription factor that is highly expressed in glutamatergic early-born cortical neurons. In Tbr1-deficient mice, these early-born neurons had molecular and functional defects. Cajal-Retzius cells expressed decreased levels of Reelin, resulting in a reeler-like cortical migration disorder. Impaired subplate differentiation was associated with ectopic projection of thalamocortical fibers into the basal telencephalon. Layer 6 defects contributed to errors in the thalamocortical, corticothalamic, and callosal projections. These results show that Tbr1 is a common genetic determinant for the differentiation of early-born glutamatergic neocortical neurons and provide insights into the functions of these neurons as regulators of cortical development.

We report on the expression pattern of a novel EGF- containing gene named Maeg. RNA in situ studies indicate that Maeg is first activated during specification of the early lateral dermatome, and continues to be expressed in all the dermatome derivatives as the dermis of the trunk, the hair follicles, and the mesenchyme of the cranio-facial region.

We isolated a novel mouse gene, RP42, in a systematic search for genes expressed in proliferating neuroblasts whose human orthologs map to suspectibility loci for autism. This gene is intronless and encodes a putative 259-amino-acid protein that exhibits 30–36% overall sequence identity to a fission yeast and a nematode protein (GenPept Accession Nos. CAA17006 and CAB54261). Nevertheless, no homology to any known gene was found. RP42 has developmentally regulated expression, particularly in proliferating neuroblasts from which neocortical neurons originate. Its human ortholog is located in a cluster of embryonic neuronally expressed genes on the 6q16 chromosome, making it a positional candidate susceptibility gene for autism.

The members of the T-box gene family share a highly conserved DNA binding domain named the T-domain, and important developmental functions. Here we report the cloning of chicken Tbr1and of murine and chickenTbr2 (orthologs of the Xenopus eomesodermin gene), the mapping of the murine Tbr2 to chromosome 9, and their pattern of expression during mouse and chick embryogenesis. Both Tbr 1 and 2 have a restricted and conserved domain of expression in the telencephalic pallium of the two species. Chick Tbr2 has a specific and dynamic expression in the gastrulating embryo.

The single-minded (sim) gene encodes a transcriptional regulator that functions as a key determinant of central nervous system (CNS) midline development in Drosophila. We report here the identification of two murine homologs of sim, Sim1 and Sim2, whose products show a high degree of sequence conservation with Drosophila SIM in their amino-terminal halves, with each containing a basic helix-loop-helix domain as well as a PAS domain. Sim1 maps to the proximal region of mouse chromosome 10, whereas Sim2 maps to a portion of the distal end of chromosome 16 that is syntenic to the Down syndrome critical region of human chromosome 21. Recent exon-trapping studies have identified in the critical region several exons of a human sim homolog which appears to be the homolog of murine Sim2; this has led to the hypothesis that increased dosage of this sim homolog in cases of trisomy 21 might be a causal factor in the pathogenesis of Down syndrome. We have examined the expression patterns of the Sim genes during embryogenesis. Both genes are expressed in dynamic and selective fashion in specific neuromeric compartments of the developing forebrain, and the expression pattern of Sim2 provides evidence for early regionalization of the diencephalon prior to any overt morphological differentiation in this region. Outside the CNS, Sim1 is expressed in mesodermal and endodermal tissues, including developing somites, mesonephric duct, and foregut. Sim2 is expressed in facial and trunk cartilage, as well as trunk muscles. Both murine Sim genes are also expressed in the developing kidney. Our data suggest that the Sim genes play roles in directing the regionalization of tissues where they are expressed. Moreover, the expression pattern documented for Sim2 may provide insights into its potential roles in Down syndrome.

The mechanisms that regulate regional specification and evolution of the cerebral cortex are obscure. To this end, we have identified and characterized a novel murine and human gene encoding a putative transcription factor related to the Brachyury (T) gene that is expressed only in postmitotic cells. T-brain-1 (Tbr-1) mRNA is largely restricted to the cerebral cortex, where during embryogenesis it distinguishes domains that we propose may give rise to paleocortex, limbic cortex, and neocortex. Tbr-1 and Id-2 expression in the neocortex have discontinuities that define molecularly distinct neocortical areas. Tbr-1 expression is analyzed in the context of the prosomeric model. Topological maps are proposed for the organization of the dorsal telencephalon.

The pattern of RNA expression of the murine Dlx-2 (Tes-1) homeobox gene is described in embryos ranging in age from E8.5 through E11.5. Dlx-2 is a vertebrate homologue of the Drosophila Distal-less (Dll) gene. Dll expression in the Drosophila embryo is principally limited to the primordia of the brain, head and limbs. Dlx-2 is also expressed principally in the primordia of the forebrain, head and limbs. Within these regions it is expressed in spatially restricted domains. These include two discontinuous regions of the forebrain (basal telencephalon and ventral diencephalon), the branchial arches, facial ectoderm, cranial ganglia and limb ectoderm. Several mouse and human disorders have phenotypes which potentially are the result of mutations in the Dlx genes.

In order to isolate genes involved in development of the mammalian telencephalon we employed an efficient cDNA library procedure. By subtracting an adult mouse telencephalic cDNA library from an embryonic day 15 (E15) mouse telencephalic cDNA library we generated two subtracted libraries (ES1 and ES2). We estimate that ES1 contains between 200 and 600 different cDNA clones, which approximates the number of genes that are preferentially expressed in the E15 telencephalon, compared to the adult telencephalon. Northern analysis of 20 different cDNA clones shows that 14 of these are expressed at least 5-fold more in the E15 telencephalon than the adult telencephalon. Limited sequencing of the 14 differentially expressed clones reveals that 10 have no significant identity to sequences in GenBank and EMBL databases, whereas the other 4 have significant sequence identity to vimentin, histone 3.3, topoisomerase I and the B2 repeat element. In situ hybridization using one of the differentially expressed cDNAs, TES-1, demonstrates that it is transiently expressed in the anlage of the basal ganglia. In situ hybridization with another differentially expressed cDNA clone, TES-4, shows that it is specifically expressed in differentiating cells of the neural axis with a distinctive rostral-caudal temporal pattern. These findings, and the methods that we have developed, provide a framework for future investigations of the genetic control of telencephalon development.