Samuel Jesuadian

LINE-1 (L1) retrotransposons are a noted source of genetic diversity and disease in mammals. To
expand its genomic footprint, L1 must mobilize in cells that will contribute their genetic material
to subsequent generations. Heritable L1 insertions may therefore arise in germ cells and in
pluripotent embryonic cells, prior to germline specification, yet the frequency and predominant
developmental timing of such events remain unclear. Here, we applied mouse retrotransposon
capture… Show more

LINE-1 (L1) retrotransposons are a noted source of genetic diversity and disease in mammals. To
expand its genomic footprint, L1 must mobilize in cells that will contribute their genetic material
to subsequent generations. Heritable L1 insertions may therefore arise in germ cells and in
pluripotent embryonic cells, prior to germline specification, yet the frequency and predominant
developmental timing of such events remain unclear. Here, we applied mouse retrotransposon
capture sequencing (mRC-seq) and whole-genome sequencing (WGS) to pedigrees of C57BL/6J
animals, and uncovered an L1 insertion rate of ≥1 event per 8 births. We traced heritable L1
insertions to pluripotent embryonic cells and, strikingly, to early primordial germ cells (PGCs).
New L1 insertions bore structural hallmarks of target-site primed reverse transcription (TPRT)
and mobilized efficiently in a cultured cell retrotransposition assay. Together, our results
highlight the rate and evolutionary impact of heritable L1 retrotransposition, and reveal
retrotransposition-mediated genomic diversification as a fundamental property of pluripotent
embryonic cells in vivo. Show less

Early fetal and placental MSCs have translationally-advantageous characteristics compared to later pregnancy MSCs. During the first trimester, the fetus and placenta grow rapidly with divergent developmental requirements, but studies comparing mesenchymal stem cells (MSCs) from different origins have paid little attention to the effect of gestational age over this temporal window. Here we present the transcriptome through first trimester development of MSC isolated from fetal bone marrow (BM)… Show more

Early fetal and placental MSCs have translationally-advantageous characteristics compared to later pregnancy MSCs. During the first trimester, the fetus and placenta grow rapidly with divergent developmental requirements, but studies comparing mesenchymal stem cells (MSCs) from different origins have paid little attention to the effect of gestational age over this temporal window. Here we present the transcriptome through first trimester development of MSC isolated from fetal bone marrow (BM) or placental structures. Samples were collected weekly from 8 to 12 weeks. The raw microarray data are available on the ArrayExpress database (www.ebi.ac.uk/arrayexpress) under accession number E-TABM-1224. Additionally, the data have been integrated into the stem cell collaboration platform www.Stemformatics.org. These data provide a valuable resource for developmental biology and stem cell investigation. Show less