PgmNr M5039: A Transgenic Mouse Model for Understanding cis and trans Mechanisms of lncRNA Jpx in vivo.

Authors:
S. Carmona; B. Lin; T. Chou; S. Sun


Institutes
University of California, Irvine, Irvine, CA.


Abstract:

Mammals experience a gene dosage imbalance between males and females due to their differing number of X chromosomes. The contrasting levels of X-linked gene products are resolved by X-Chromosome Inactivation (XCI), in which the long-noncoding RNA (lncRNA) Xist is activated in females and coordinates long-term gene silencing of one X Chromosome. Jpx, another lncRNA expressed from a locus just proximal to Xist, is able to activate Xist expression by binding to and removing CTCF protein from the Xist promoter. While a Jpx deletion is lethal in differentiated female mouse embryonic stem (mES) cells, Jpx overexpression causes ectopic Xist expression in both male and female mES cells. This project aims to understand how well our knowledge of in vitro lncRNA mechanisms remain true in vivo (in a live animal), specifically for cis and trans gene regulatory mechanisms. Thus, we used a BAC transgene to produce mouse lines overexpressing Jpx [Tg(Jpx)#Shsn], or Jpx and Xist together [Tg(Jpx, Xist)#Shsn]. We found that transgenic animals are viable, visibly normal, and fertile. Both male and female parents are able to transmit the transgene to their offspring; however, in certain lines we observed a significant lack of transgenic mice derived from the male parent. We also found that Jpx and Xist expression tend to increase together when located proximally to each other (in Tg (Jpx, Xist) mice), indicating that Jpx has a cis preference in vivo. Our data suggest that Jpx holds a consistent mechanism in vitro and in vivo, and thatJpx may have an unstudied role in spermatogenesis and imprinting.