Article

Functional complementation of Glra1(spd-ot), a glycine receptor subunit mutant, by independently expressed C-terminal domains.

Institut für Biochemie, Emil-Fischer-Zentrum, Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
Journal of Neuroscience (impact factor: 7.11). 03/2009; 29(8):2440-52. DOI:10.1523/JNEUROSCI.4400-08.2009 pp.2440-52
Source: PubMed

ABSTRACT The oscillator mouse (Glra1(spd-ot)) carries a 9 bp microdeletion plus a 2 bp microinsertion in the glycine receptor alpha1 subunit gene, resulting in the absence of functional alpha1 polypeptides from the CNS and lethality 3 weeks after birth. Depending on differential use of two splice acceptor sites in exon 9 of the Glra1 gene, the mutant allele encodes either a truncated alpha1 subunit (spd(ot)-trc) or a polypeptide with a C-terminal missense sequence (spd(ot)-elg). During recombinant expression, both splice variants fail to form ion channels. In complementation studies, a tail construct, encoding the deleted C-terminal sequence, was coexpressed with both mutants. Coexpression with spd(ot)-trc produced glycine-gated ion channels. Rescue efficiency was increased by inclusion of the wild-type motif RRKRRH. In cultured spinal cord neurons from oscillator homozygotes, viral infection with recombinant C-terminal tail constructs resulted in appearance of endogenous alpha1 antigen. The functional rescue of alpha1 mutants by the C-terminal tail polypeptides argues for a modular subunit architecture of members of the Cys-loop receptor family.

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Keywords

9 bp microdeletion
 
alpha1 mutants
 
C-terminal missense sequence
 
C-terminal tail polypeptides
 
complementation studies
 
cultured spinal cord neurons
 
Cys-loop receptor family
 
deleted C-terminal sequence
 
differential use
 
endogenous alpha1 antigen
 
exon 9
 
functional alpha1 polypeptides
 
Glra1 gene
 
glycine receptor alpha1 subunit gene
 
glycine-gated ion channels
 
lethality 3 weeks
 
mutant allele encodes
 
oscillator mouse
 
recombinant C-terminal tail constructs
 
truncated alpha1 subunit