1. ERα directly binds to pri‐miR‐22
ERα directly binds to pri‐miR‐22 ARNA immunoprecipitation using HEK293 cells transfected with ERα‐FLAG and pri‐miR‐22 variants indicate an interaction between the WT pri‐miR‐22 (WT), but not with mutants containing a mutated ERE site (mut) or with a control construct with mutated ERE and miR‐22 replaced by miR‐1 sequences (con).B–DIn vivo mutation of the identified ERα binding element (ERE, see Fig 6A) in the first exon of the miR‐22 host gene to a loxP site (miR‐22d/d; B) abolished the differences in the abundance of mature miR‐22 (C; miR‐22d/d male, n = 22; miR‐22d/d female, n = 18; two‐tailed unpaired t‐test) and of pri‐miR‐22 between male and female animals (D, miR‐22d/d male, n = 23; miR‐22d/d female, n = 17; two‐tailed unpaired t‐test). Data were normalized to U6 (C) or Rplp0 (D), respectively, and WT female values were used as reference. Data are presented as mean ± SEM.EIn summary, miR‐22 is expressed predominantly in striated muscle tissue, and at the posttranscriptional level, ERα represses the processing of miR‐22 host RNA to mature miR‐22 by direct binding to an ERE‐like sequence in the miRNA host RNA. This results in higher abundance of mature miR‐22 in male compared to female muscle. Accordingly, complete disruption of ERα increases mature miR‐22 and decreases the pri‐miR‐22 concentration (blue arrows). The miRNA miR‐22 represses in vivo the activity of the direct target ERα especially in male muscle. Repressed ERα abundance in wild‐type male muscle tissue is essential to restrict the effects of ERα on the lipid metabolic genes and on fatty oxidation in male muscle tissue. Deletion of miR‐22 leads to increase in ERα and fatty acid oxidation and subsequently to decrease WAT and body weight in male animals (red arrows); these effects can be eliminated by additional muscle‐specific deletion of ERα (green arrows).
Judith Schweisgut et al. EMBO J. 2017;36:
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