Differential expression of nicotinic acetylcholine receptor genes in innervated and denervated chicken muscle.
We have studied the mRNAs encoding all four subunits of the acetylcholine receptor in 13-day embryonic, innervated and denervated chicken pectoral muscle. In all three states the transcript sizes of the alpha, beta-, gamma- and delta-subunit mRNAs were approximately 3.2, 2.8, 1.8 and 1.9 kb respectively. Denervation was found to result in a large increase in the steady-state levels of each mRNA compared with those in innervated muscle. This increase was 8- to 9-fold for the beta and delta subunits and approximately 12-fold for the alpha subunit. The evidence obtained shows a coordinate regulation of the acetylcholine receptor genes in response to denervation. Interestingly, no gamma-subunit transcript was detected in innervated muscle, while significant levels were detected in embryonic and denervated tissue. This evidence suggests that there exists in a non-mammalian muscle acetylcholine receptor an additional subunit, analogous to the bovine epsilon subunit, and shows that the extra-junctional receptor of adult denervated muscle is produced by the same set of mRNAs which produce the major form of the receptor in embryonic muscle.
MRC Molecular Neurobiology Unit, MRC Centre, Cambridge, UK.
S J
SJ
Moss
D M
DM
Beeson
J F
JF
Jackson
M G
MG
Darlison
E A
EA
Barnard
D000818:Animals; D002645:Chickens; D005796:Genes; D046911:Macromolecular Substances; D009121:Muscle Denervation; D009132:Muscles / Q000294:innervation* / Q000378:metabolism; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000235:genetics*; D011978:Receptors, Nicotinic / Q000235:genetics*; D014158:Transcription, Genetic
D046911:Macromolecular Substances; D012333:RNA, Messenger; D011978:Receptors, Nicotinic