Developmental profile of polyadenylated and non-polyadenylated GABAA receptor subunit mRNAs.
The ratio of mRNA not selected for polyadenylation (non-poly(A)+ selected) to mRNA selected for polyadenylation (poly(A)+) for the beta 1, alpha 1 and gamma 2 subunits of the GABAA receptor complex was examined in rats as a function of age. RNA was extracted from whole brain of rats that were either 0, 1, 3, 5 or over 60 days of postnatal age. Poly(A)+ mRNA was purified by oligo(dT)-cellulose chromatography. Non-poly(A)+ selected mRNA and poly(A)+ mRNA for the GABAA receptor beta 1, alpha 1 and gamma 2 subunits were examined by Northern blot analysis using cDNA probes specific for these subunits. Levels of GABAA receptor beta 1 subunit mRNA were also examined by solution hybridization analysis with a beta 1 riboprobe. Analysis of Northern blots revealed that levels of poly(A)+ beta 1 subunit mRNA were highest at 0 days of age, but decreased and reached adult levels by 5 days of postnatal age. However, levels of the beta 1 subunit message extracted from non-poly(A)+ selected mRNA were not significantly different at any of the ages examined, suggesting the existence of a population of beta 1 subunit mRNA that is not polyadenylated. The age-related discrepancy between beta 1 subunit levels measured in non-poly(A)+ selected mRNA and poly(A)+ mRNA was also observed using solution hybridization analysis. In contrast, levels of both non-poly(A)+ selected mRNA and poly(A)+ mRNA for the alpha 1 subunit of the GABAA complex increased from 0 days of age to adulthood. Similarly, levels of both non-poly(A)+ selected mRNA and poly(A)+ mRNA for the GABAA receptor gamma 2 subunit increased with age.(ABSTRACT TRUNCATED AT 250 WORDS)
D000375:Aging / Q000502:physiology*; D000591:Amino Acid Isomerases / Q000235:genetics; D000818:Animals; D015152:Blotting, Northern; D001921:Brain / Q000254:growth & development / Q000502:physiology*; D002352:Carrier Proteins / Q000235:genetics; D003524:Cyclosporins / Q000378:metabolism; D046911:Macromolecular Substances; D009693:Nucleic Acid Hybridization; D019696:Peptidylprolyl Isomerase; D011061:Poly A / Q000378:metabolism*; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000096:biosynthesis / Q000235:genetics*
D002352:Carrier Proteins; D003524:Cyclosporins; D046911:Macromolecular Substances; D012333:RNA, Messenger; D011963:Receptors, GABA-A; D011061:Poly A; D012313:RNA; D000591:Amino Acid Isomerases; D019696:Peptidylprolyl Isomerase