Poster Presentation 44th Lorne Genome Conference 2023

LINE-1 activity in mammalian primordial germ cell specification (#104)

Renee R. Chu 1 , Alexander L. Carleton 1 , Stephanie E. Workman 1 , Adam D. Ewing 1 , Sandra R. Richardson 1
  1. Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Brisbane, Queensland, Australia

Long Interspersed Element 1 (LINE-1 or L1) is an autonomously mobile retrotransposon found throughout mammalian genomes. L1s have the capability to retrotranspose, or “jump” into other regions of our genome. Most importantly, as “selfish” elements, L1s must create new copies in cells that can be passed down to the next generation, which can lead to cellular dysfunction and genetic disease. Our cells have evolved defence mechanisms to impede L1 retrotransposition. Previously, Richardson et al. 2017 demonstrated that L1 can retrotranspose in early mouse primordial germ cells (PGCs)1. PGCs are specified early during mammalian embryonic development, ultimately giving rise to all germ cells of an adult organism. As a novel niche, little is known about the dynamics of L1 activity and regulation during PGC specification. Early mouse PGCs in vivo are technically challenging to study due to the requirement of cell specificity and small cell number with a founding population of approximately 40 PGCs. Hence, using a stable mESC cell line expressing Stella/GFP and Esg1/tdTomato (SGET or traffic light system), we are developing a model to investigate regulation of L1 expression and retrotransposition during the specification of primordial germ cell-like cells (PGCLCs) from mouse embryonic stem cells (mESCs) in vitro using a BFP-based L1 retrotransposition indicator construct2,3. Our work will shed light on the unexplored interplay between L1 activity and genomic defenses in this critical developmental niche.

  1. Richardson SR, Gerdes P, Gerhardt DJ, Sanchez-Luque FJ, Bodea GO, Muñoz-Lopez M, et al. Heritable L1 retrotransposition in the mouse primordial germline and early embryo. Genome Res. 2017;27(8):1395-405.
  2. Hayashi K, Ohta H, Kurimoto K, Aramaki S, Saitou M. Reconstitution of the mouse germ cell specification pathway in culture by pluripotent stem cells. Cell. 2011;146(4):519-32.
  3. Hackett JA, Huang Y, Günesdogan U, Gretarsson KA, Kobayashi T, Surani MA. Tracing the transitions from pluripotency to germ cell fate with CRISPR screening. Nature Communications. 2018;9(1):4292.