Stereotyped distribution of midbody remnants in early C. elegans embryos requires cell death genes and is dispensable for development

The midbody is a structure formed within the intercellular bridge towards the end of cytokinesis¹. Microtubules within this bridge are then severed on one side of the midbody during abscission, thus generating a midbody remnant in one of the resulting daughter cells. Midbody remnants persist long after cell division and accumulate preferentially in stem cells, induced pluripotent stem (iPS) cells, and cancer stem cells^2,3,4. Upon induction of differentiation, midbody remnants are degraded by autophagy or released into the extracellular milieu in some tissue culture cells, and it has been proposed that such removal is critical for enabling a differentiation program^2,3,4. However, the fate of midbody remnants in a developing organism remains elusive, and whether their presence plays a role in cell fate determination in vivo is not known.

We next investigated the mechanisms directing the internalization of the P₀ and AB midbody remnants almost exclusively into the EMS lineage and not into ABa or ABp, which are also in contact with these midbody remnants. We first tested whether such stereotyped distribution is under the control of anterior-posterior (A-P) polarity cues. We used RNAi to deplete par-2 and par-3, which are essential for the A-P polarity, and found that the P₀ and AB midbody remnants are internalized indiscriminately by either an anterior or posterior blastomere in such embryos (Figure 1B, Supplementary information, Figure S2C, S2D, S2F and S2G). Therefore, A-P polarity contributes to directing midbody remnant segregation in early C. elegans embryos.

Log in or create a free account to read this content

Gain free access to this article, as well as selected content from this journal and more on nature.com

Access through your institution

or

Sign in or create an account

Continue with Google

Continue with ORCiD