A lineage problem seems most likely, especially in accord with the slow growth. But for some cell types as they age, nuclei are known to disappear by
phagocytosis (as in intestine) (McGee et al, 2011) or to lose integrity and fade dramatically without completely disappearing (bodywall muscle)
(Herndon et al., 2002). Is there a time point when nuclei reach a maximum number and then begin to vanish, or is there a deficiency
in the number of nuclei at each time point for the mutant?
Let me rephrase what I said here about the disappearance of intestinal cell nuclei. This process occurs by engulfment of the nucleus by an autophagosome
within the intestinal cytoplasm of the aging animal. Thus the organelle is self-eliminated by the intestinal cell itself, and cannot be properly termed
“phagocytosis”, as that term would suggest that the nucleus had been removed by a neighboring scavenger cell.
This still begs the question as to how a mutation may lead to the hypodermal syncytium holding too few nuclei as the mutant animal develops and ages.
Could be a defect in the hyp lineage divisions, a loss of nuclei after their creation, or possibly an effect due to poorer staining properties as the mutant ages.
Thanks so much! I hadn’t considered the possibility of them disappearing.
At this point, we only know that the nuclei number is reduced at the 2-day adult stage. It sound’t like we need to look at this over time to see if they disappear or are never formed. I’m assuming it would be best to measure this at each larval stage and then into the first few days of adulthood.
Are you aware of any other strains with reduced hypodermal nuclei numbers?