Skeletal muscle LINE-1 retrotransposon activity is upregulated in older versus younger rats.

Skeletal muscle LINE-1 retrotransposon activity is upregulated in older versus younger rats. Am J Physiol Regul Integr Comp Physiol. 2019 Jun 12;: Authors: Mumford PW, Romero MA, Osburn SC, Roberson PA, Vann CG, Mobley CB, Brown MD, Kavazis AN, Young KC, Roberts MD Abstract Long Interspersed Element-1 (LINE-1) is a retrotransposon capable of replicating and inserting LINE-1 copies into the genome. Others have reported skeletal muscle LINE-1 markers are higher in older versus younger mice, but data are lacking in other species. Herein, gastrocnemius muscle from male Fischer 344 rats that were 3, 12, and 24 months (mo) (n=9 per group) were analyzed for LINE-1 mRNA, DNA, promoter methylation and DNA accessibility. qPCR primers were designed for active (L1.3) and inactive (L1.Tot) LINE-1 elements as well as part of the ORF1 sequence. L1.3, L1.Tot and ORF1 mRNAs were higher (p<0.05) in 12/24 versus 3 mo rats. L1.3 DNA was higher in the 24 mo rats versus other groups, and ORF1 DNA was greater in 12/24 versus 3 mo rats. ORF1 protein was higher in 12/24 versus 3 mo rats. RNA-sequencing indicated mRNAs related to DNA methylation (TET1) and histone acetylation (HDAC2) were lower in 24 versus 3 mo rats. L1.3 DNA accessibility was higher in 24 versus 3 mo rats. No age-related differences in nuclear histone deacetylase (HDAC) activity existed, although nuclear DNA methyltransferase (DNMT) activity was lower in 12/24 versus 3 mo rats (p<0.05...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - Category: Physiology Authors: Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research