Isolation and sequence of cDNA clones coding for the precursor to the γ subunit of mouse muscle nicotinic acetylcholine receptor
✍ Scribed by J. Boulter; K. Evans; G. Martin; P. Mason; S. Stengelin; D. Goldman; S. Heinemann; J. Patrick
- Publisher
- John Wiley and Sons
- Year
- 1986
- Tongue
- English
- Weight
- 923 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0360-4012
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✦ Synopsis
cDNA libraries have been constructed in plasmid (pBR322) and bacteriophage (XgtlO) vectors with poly (A+) RNA isolated from the nonfusing mouse muscle cel! line BC3H-1. The libraries were screened with a restriction fragment derived from a genomic clone coding for a human acetylcholine receptor y subunit. Several clones were obtained whose cDNA inserts possessed nucleotide and deduced amino acid sequence homology with acetylcholine receptor y subunits from Torpedo culifomicu, chick, calf, and human. One isolate, XBMG419, has 88 nucleotides of 5 'antranslated sequence, an open reading frame of 1,557 nucleotides coding for the precursor to the mouse acetylcholine receptor y subunit, and 144 nucleotides of 3'-untranslated sequence. Alignment of the XBMG419-deduced amino acid sequence with homologs from other species predicts a precursor peptide of 519 amino acids and a mature protein of 497 amino acids, with nonglycosylated molecular weights of 58,744 and 56,424 daltons, respectively. Comparison of the deduced amino acid sequence of the mouse y subunit with Torpedo, chick, calf, and human sequences showed overall homologies of 54%, 67 % , 90%, and 90%, respectively; however, significantly higher homologies were found in several putative functional domains. Radiolabeled XBMG419 has been used to identify homologous RNA species, one of approximately 2 kb and one of about 3.5 kb, in poly (A+) RNA prepared from BC3H-1 cells and denervated mouse limb muscle. y Subunit-coding RNA species are considerably more abundant in denervated than in innervated muscle, suggesting that neural regulation of the abundance of the y subunit is exerted through regulation of the amount of its mRNA.