GABRB3, GABRA5, GABRG3 (conflicting data)






The GABAA receptor subunit gene expression was detected from mouse A9 hybrids containing a single human paternal chromosome 15, but not from cells containing a maternal chromosome 15, leading to the conclusion that human GABRB3, GABRA5, GABRG3 are imprinted (paternally expressed). Unexpectedly there was evidence of paternal methylation at the 5 end of GABRB3 (Meguro M et al, 1997). Previously Kubota T et al (1994) reported possible paternal silencing of GABRB3 on the basis of undetectable expression in a single hydatidiform mole.
Presence of a 50-60 kb domain of allele-specific replication between the γ-aminobutyric acid receptor subunit β3 (GABRB3) and α5 (GABRA5) genes were reported (LaSalle M J and Lalande M, 1994)
All three genes were biallelically expressed in 21 brain samples (Hogart A et al, 2007).
Reduced expression levels of GABRA5 and GABRB3, measured by microarray and quantitative RT-PCR, were noted in cells from PWS with maternal UPD suggesting higher expression levels from the paternal allele (Bittel DC et al, 2003).
GABRB3 showed significantly reduced expression in multiple Rett, Angelman and autism human brain samples and in Mecp2 deficient mice, by quantitative immunoblot suggesting that the reduced levels of GABRB3 were attributable to altered neuronal function rather than imprinting (Samaco RC et al, 2005).
Transmission disequilibrium test analysis has provided evidence for paternal (but not maternal) transmission of GABRA5 and GABRB3 in association with alcoholism (P < 0.004 and P < 0.007 respectively) (Jiuzhou S et al, 2003). In contrast others have failed to confirm any parent-or-origin effects for alcoholism at this locus (Dick DM et al, 2004).
Morcos L et al (2011) found no evidence of allelic expression bias in fibroblast cell lines for GABRB3 and GABRA5 and for GABRG3 no evidence of imprinting was found in the lymphoblast cell lines investigated.





Last Modified 5/26/2013


OMIM (GABRB3)   OMIM (GABRA5)   OMIM (GABRG3)   Gene (GABRB3)   Gene (GABRA5)   Gene (GABRG3)  

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