Manipulating Chromosomal Content In Zebrafish Embryos And Determining The Effects On Differentiation Of Neuromesodermal Progenitor Cells

A body of evidence suggests that increased ploidy aids cells in development, differentiation, homeostasis, and wound healing. With increased size and transcription, polyploid cells are capable of genomic buffering against mutations and resistance to apoptosis. Currently, research surrounding the impact of polyploidy driven cell changes is plant focused and investigations with animal cells are lacking. Interestingly, our lab found neuromesodermal progenitors (NMps) are held in an extended S/G2, with double the DNA content, prior to differentiating during zebrafish somitogenesis. These NMps may be mimicking polyploid cells in order to aid differentiation. The present study establishes a zebrafish model system with various ploidy levels. We documented the length and morphology at 5 days post fertilization, where suspected haploid and tetraploid zebrafish were both shorter in length compared to their diploid counterparts. Our study followed NMp differentiation by comparing gene expression domains across ploidy levels. NMps destined to become skeletal muscle express four key genes in consecutive order, tbxta, tbx16, tbx6, and myoD. Our results suggest that reduction in ploidy disrupts mechanisms involved in somite formation while increased ploidy increases the adaptability of cells to respond to acute stress because NMps remain capable of differentiating normally toward the muscle fate.