Sequence Characterization of Bovine Antisense to Insulin-Like Growth Factor Type 2 Receptor Non-Coding RNA (AIRN)

Abstract

Bovine insulin-like growth factor type 2 receptor (IGF2R) is an imprinted gene whose aberrant expression has been implicated in development of abnormal offspring syndrome. Bovine AIRN (AIRN) is expressed in post-implantation fetal tissues coinciding with imprinted expression of IGF2R. Although expression patterns of bovine AIRN have been reported based on PCR analysis, characteristics of this transcript are unknown. Therefore, the objective of this work was to sequence characterize the AIRN ncRNA transcript. PCR primer sets (n = 19) were designed based on genomic sequence to “walk” down the predicted AIRN ncRNA sequence. Total RNA extracted from gestational day 150 bovine fetal liver was used as source material for analysis. Extracted RNA was DNase-treated prior to cDNA synthesis, PCR amplified, and sequenced. A putative bAIRN promoter was located 623 base-pairs upstream of differentially methylated region 2 (DMR2) within intron 2 of IGF2R. A polyadenylation signal was found 117 kb downstream of the promoter. Primer sets designed upstream of the promoter as well as downstream of the polyadenylation signal yielded no PCR amplicons, suggesting that the length of AIRN is approximately 117 kb. In conclusion, bovine AIRN appears to be an antisense transcript of approximately 117 kb in length with a promoter region located 623 bp upstream of DMR2 within intron 2 of IGF2R.