Age related obesity-induced shortening of GLUT4 mRNA poly(A) tail length in rat gastrocnemius skeletal muscle.
Obese insulin resistant animals and humans have shown reduced GLUT4 gene expression. Yet, in skeletal muscle, discrepancy between mRNA and protein regulation has been frequently observed, suggesting a post-transcriptional modulation. We investigated the GLUT4 expression in adipose tissue and muscle of obese 12-month-old (12-mo) rats, comparing with lean 2-month-old (2-mo) animals. Obesity was accompanied by insulin resistance, and 65% reduction (P<0.01) in GLUT4 mRNA and protein in adipose tissue. However, in muscle, despite increased (P<0.05) mRNA content, GLUT4 protein was unchanged. RNase H and poly(A) test assays showed a reduction (P<0.01) of approximately 80 adenines in the GLUT4 mRNA poly(A) tail of muscle from 12-mo rats, recognizing that the poly(A) tail length correlates with translation efficiency. Concluding, age related obesity of 12-mo rats involves suppression of GLUT4 expression in adipose tissue; however, in muscle, GLUT4 mRNA content increases, but with a shorter poly(A) tail, thus unchanging the protein content.
Seraphim
Patricia Monteiro
PM
Department of Physiotherapy, University of State of Sao Paulo, Presidente Prudente, Sao Paulo, Brazil.
Nunes
Maria Tereza
MT
Giannocco
Gisele
G
Machado
Ubiratan Fabres
UF
D000225:Adenine; D052436:Adipose Tissue, White / Q000378:metabolism; D000375:Aging; D000818:Animals; D005786:Gene Expression Regulation; D051275:Glucose Transporter Type 4 / Q000235:genetics* / Q000378:metabolism; D007333:Insulin Resistance; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D009765:Obesity / Q000235:genetics* / Q000473:pathology; D011061:Poly A / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D051275:Glucose Transporter Type 4; D012333:RNA, Messenger; D011061:Poly A; D000225:Adenine