Year-end Sale % OFF 
Abstract
N-methyl-d-aspartate receptors (NMDARs) play an important role in many aspects of nervous system function such as synaptic plasticity and neuronal development. NMDARs are heteromers consisting of an obligate NR1 and most commonly one or two kinds of NR2 subunits. While the receptors have been well characterized in some vertebrate and invertebrate systems, information about NMDARs in Xenopus laevis brain is incomplete. Here we provide biochemical evidence that the NR1, NR2A and NR2B subunits of NMDARs are expressed in the central nervous system of X. laevis tadpoles. The NR1-4a/b splice variants appear to be the predominant isoforms while the NR1-3a/b variants appear to be expressed at low levels. We cloned the X. laevis NR2A and NR2B subunits and provide a detailed annotation of their functional domains in comparison with NR2A and NR2B proteins from 10 and 13 other species, respectively. Both NR2A and NR2B proteins are remarkably well conserved between species, consistent with the importance of NMDARs in nervous system function.
Highlights
N-methyl-D-aspartate receptors (NMDARs) are ligand-gated ionotropic glutamate receptors that are important mediators for neuronal events such as synaptic plasticity, learning and memory, neuronal development and circuit formation, and have been implicated in various neuronal disorders (Cull-Candy et al, 2001; Dingledine et al, 1999; Hua and Smith, 2004; Riedel et al, 2003; Waxman and Lynch, 2005)
Since antibodies generated against X. laevis-specific NMDAR subunits are not available, we probed with antibodies generated against the rat homologs and found cross-reactive bands for X. laevis NR1 (∼120 kD), NR2A (∼180 kD) and NR2B (∼180 kD) that run approximately at the same size as the bands found in rat whole brain lysate (Figure 1A)
This could be due to the predominance of the smallest NR1 splice variant, NR1-4b, in X. laevis (Soloviev et al, 1996; this paper), which is less abundant in rat (Durand et al, 1992, 1993; Hollmann et al, 1993; Sugihara et al, 1992)
Summary
N-methyl-D-aspartate receptors (NMDARs) are ligand-gated ionotropic glutamate receptors that are important mediators for neuronal events such as synaptic plasticity, learning and memory, neuronal development and circuit formation, and have been implicated in various neuronal disorders (Cull-Candy et al, 2001; Dingledine et al, 1999; Hua and Smith, 2004; Riedel et al, 2003; Waxman and Lynch, 2005). The examination of sequence conservation across species provides an indication of critical amino acids and domains required for NMDAR function in nervous system plasticity. Expression of the NR1 isoforms and the NR2 subunits is developmentally and spatially regulated (Laurie and Seeburg, 1994; Monyer et al, 1994), indicating a functional significance for specific NMDAR subunit compositions during nervous system development. While NMDARs have been cloned and very well studied in other vertebrate (Cox et al, 2005; Dingledine et al, 1999; Laurie et al, 1997; Monyer et al, 1994; Moriyoshi et al, 1991; ZarainHerzberg et al, 2005) and invertebrate systems (Brockie et al, 2001; Xia et al, 2005), NMDARs in Xenopus laevis have only been partially characterized (Schmidt et al, 2006; Soloviev et al, 1996)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
