Gene structure and expression of the targeting subunit, RGL, of the muscle-specific glycogen-associated type 1 protein phosphatase, PP1G.
The type I phosphatase associated with glycogen, PP1G, plays an important role in glycogen metabolism. PP1G is targeted to glycogen by the R(GL) subunit, which regulates the function of the enzyme. We report the cloning and characterization of the gene as well as the pattern of expression of the R(GL) subunit from mouse. The gene covers more than 37 kb, is composed of four exons and three introns, and codes for a 1089 residue polypeptide with a calculated molecular weight of 121,000. The amino acid sequence has 60% identity with the human and rabbit R(GL). The 5' flanking region of the gene contains a TATA box, c-Myc sites, and a potential cAMP-responsive element. Muscle specific motifs, such as MyoD and MEF-2, were also found. The A-T rich 3'-UTR contained several polyadenylation signals, two associated with poly(A) down-stream consensus motifs. ARE elements, which regulate mRNA stability, were dispersed throughout the 3'-UTR. Northern analysis of poly(A) mRNA from various murine tissues indicates a major transcript of 7.5 kb in skeletal muscle and heart. Western analysis demonstrates that R(GL) protein is present in skeletal and cardiac muscle from mouse, rat, and rabbit but not in L6 myoblasts, L6 myotubes, 3T3 L1 fibroblasts, 3T3 L1 or rat primary adipocytes, confirming that expression of the gene is specific to striated muscle. Analysis of skeletal muscle from rats made diabetic by streptozotocin treatment reveals that the level of R(GL) protein is the same as in control animals, indicating that expression is not regulated by insulin.
Lannér
C
C
Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202-5122, USA.
Suzuki
Y
Y
Bi
C
C
Zhang
H
H
Cooper
L D
LD
Bowker-Kinley
M M
MM
DePaoli-Roach
A A
AA
D020413:3' Untranslated Regions; D017667:Adipocytes / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics*; D002478:Cells, Cultured; D003001:Cloning, Molecular; D000242:Cyclic AMP / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D005091:Exons; D015723:Gene Library; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007438:Introns; D064326:MEF2 Transcription Factors; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism; D009132:Muscles / Q000201:enzymology*; D017570:MyoD Protein / Q000378:metabolism; D018006:Myogenic Regulatory Factors; D010749:Phosphoprotein Phosphatases / Q000737:chemistry* / Q000235:genetics*; D011110:Polymorphism, Genetic; D014176:Protein Biosynthesis; D054645:Protein Phosphatase 1; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D017386:Sequence Homology, Amino Acid; D013311:Streptozocin / Q000494:pharmacology; D014018:Tissue Distribution; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
D020413:3' Untranslated Regions; D002352:Carrier Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D007328:Insulin; D064326:MEF2 Transcription Factors; D017570:MyoD Protein; D018006:Myogenic Regulatory Factors; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D014157:Transcription Factors; D013311:Streptozocin; D000242:Cyclic AMP; D010749:Phosphoprotein Phosphatases; C498442:Ppp1r3b protein, mouse; C114052:Ppp1r3b protein, rat; D054645:Protein Phosphatase 1