@article{d6bd49792d924899a417018cfbb82080,
title = "Identification and expression of a unique neonatal variant of the GABAA receptor α3 subunit",
abstract = "The GABAA receptor provides the majority of inhibitory neurotransmission in the adult central nervous system but in immature brain is responsible for much of the excitatory drive, a requirement for normal brain development. It is well established that GABAA receptor subunit expression changes across the course of brain development. In the present study, we have identified a splice variant of the GABAA receptor α3 subunit which appears unique to the developing brain, referred to here as the GABAA receptor α3 subunit neonatal variant (GABAA receptor α3N). RT-PCR and sequence analysis revealed splicing of exon 8 of the α3 subunit. Western blot analysis showed expression of GABAA receptor α3N in the cortex of several neonatal species and significantly reduced expression of this splice variant in the corresponding adult brains. Expression was evident in multiple brain regions and decreased across development in the pig. Fractionation revealed differential cellular localisation in the parietal cortex, hippocampus and thalamus of the full-length GABAA receptor α3 and GABAA receptor α3N. Immunoprecipitation showed direct interaction with the GABAA receptor subunits α1 and γ2 but not with gephyrin.",
keywords = "Development, GABA receptor, Neonatal",
author = "Miller, {Stephanie M.} and Samuel Pelly and Kalanjati, {Viskasari P.} and Aven Lee and Colditz, {Paul B.} and Bjorkman, {S. Tracey}",
note = "Funding Information: Fig. 4 Cellular localisation of GABAA receptor α3 protein and α3N variant. Parietal cortex, hippocampus, and thalamus samples from two fetal ages (91 and 100 days GA) and two postnatal ages (P4 and adult) were fractionated to obtain the nuclear, cytoplasmic, and membrane fractions. Western blot analysis revealed localisation of both the full-length GABAA receptor α3 protein and α3N variant to nuclear and membrane fractions, although α3N variant expression was higher in developing fetal brain compared with postnatal ages. Cytosolic expression of both proteins was much lower; however, there was a distinct switch in abundance of the α3 and α3N variant expression with age. Full-length cytosolic GABAA receptor α3 was expressed almost exclusively in fetal brain while the α3N variant was exclusively expressed in the postnatal brain. Parietal cortex showed overlap of α3 and α3N expression closer to birth, but by adulthood, only the α3N variant was expressed in the cytosol. N=Nuclear (5 µg), M=membrane (5 µg), C = cytosolic (20 µg) Fig. 5 Immunoprecipitation of pig brain lysates with GABAA receptor subunit α3, α1, γ2, and gephyrin antibodies. Captured immuno-complexes were subjected to western blot analysis and probed with the same antibodies. Immunoblots with anti-GABAA receptor α3 (Blot-α3) show co-precipitation of both full-length α3 (55 kDa) and variant α3N (49 kDa) proteins with GABAA receptor subunits α1 and γ2, but not with gephyrin. Reverse immunoblots with anti-GABAA receptor α1 (Blot-α1) and anti-GABAA receptor γ2 (Blot-γ2) confirmed this interaction. Gephyrin was found to interact only with GABAA receptor γ2 in pig brain Acknowledgements Financial support was provided by The National Health and Medical Research Council (Australia) (Grant ID: 569826 and 351501). STB is supported by a Lion{\textquoteright}s Medical Research Foundation Senior Fellowship. PBC is supported by an NHMRC Practitioner Fellowship. VPK is a recipient of an Australian Development Scholarship. Thanks to Morgan Apel and Jack Kibble for technical assistance. Funding Information: Financial support was provided by The National Health and Medical Research Council (Australia) (Grant ID: 569826 and 351501). STB is supported by a Lion?s Medical Research Foundation Senior Fellowship. PBC is supported by an NHMRC Practitioner Fellowship. VPK is a recipient of an Australian Development Scholarship. Thanks to Morgan Apel and Jack Kibble for technical assistance. The authors declare no conflict of interest. Publisher Copyright: {\textcopyright} 2017, Springer-Verlag GmbH Germany, part of Springer Nature.",
year = "2018",
month = mar,
day = "1",
doi = "10.1007/s00429-017-1597-6",
language = "English",
volume = "223",
pages = "1025--1033",
journal = "Brain Structure and Function",
issn = "1863-2653",
publisher = "Springer Verlag",
number = "2",
}