Amitosis and endocycles in early cultured mouse trophoblast

Kuhn, Evelyn M.; Therman, Eeva; Susman, Barbara

doi:10.1016/0143-4004(91)90006-2

Cited by 25 publications

(16 citation statements)

References 20 publications

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“…First, the nuclear invagination that we observed at 8 hours of re-feeding, more prominent on one side of the nucleus (Figure 3A–B), was reminiscent of that reported in the Tetrahymena macronucleus (Endo and Sugai, 2011), cricket egg follicle cells (Conklin, 1903), scorpion serosa (Johnson, 1892), rainbow trout erythrocytes (Wang et al, 2010), rat trophoblast cells (Zybina and Zybina, 2008), and human adrenal cells (Magalhaes et al, 1991) undergoing ploidy reduction. Second, the binucleate cell and characteristic bridge between the two nuclei that we observed at 16 hours of re-feeding (Figure 3C–D, yellow arrow heads) was like that reported in the Tetrahymena macronucleus (Endo and Sugai, 2011), scorpion serosa (Johnson, 1892), rainbow trout erythrocytes (Wang et al, 2010), mouse (Kuhn et al, 1991) and spotted skunk trophoblast cells (Isakova and Mead, 2004), and human fibroblasts (Walen, 2005) undergoing ploidy reduction. Finally, the lack of an α-tubulin-rich mitotic spindle was consistent with reports of cells in all above mentioned species and cell types.…”

Section: Resultssupporting

confidence: 79%

“…Reductive mitotic division has been described in the mammalian liver (Duncan et al, 2009). Amitosis has been described in a host of cell types from primitive ciliates (Prescott, 1994) to plants (Miller, 1980), fish (Wang et al, 2010), birds (Patterson, 1908), skunk (Isakova and Mead, 2004), rodents (Kuhn et al, 1991; Zybina and Zybina, 2008), and humans (Magalhaes et al, 1991). In the absence of diploid progenitor cells, why might the Drosophila midgut replace ISCs through an amitotic division rather than a mitotic one?…”

Section: Discussionmentioning

confidence: 99%

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Amitosis of Polyploid Cells Regenerates Functional Stem Cells in the Drosophila Intestine

Lucchetta

Ohlstein

2017

Cell Stem Cell

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Summary Organ fitness depends on appropriate maintenance of stem cell populations, and aberrations in functional stem cell numbers are associated with malignancies and aging. Symmetrical division is the best characterized mechanism of stem cell replacement, but other mechanisms could also be deployed, particularly in situations of high stress. Here, we show that after severe depletion, intestinal stem cells (ISCs) in the Drosophila midgut are replaced by spindle-independent ploidy reduction of cells in the enterocyte-lineage through a process known as amitosis. Amitosis is also induced by the functional loss of ISCs coupled with tissue demand and in aging flies, underscoring the generality of this mechanism. However, we also found that random homologous chromosome segregation during ploidy reduction can expose deleterious mutations through loss of heterozygosity. Together, our results highlight amitosis as an unappreciated mechanism for restoring stem cell homeostasis, but one with some associated risk in animals carrying mutations.

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Section: Resultssupporting

confidence: 79%

Section: Discussionmentioning

confidence: 99%

Amitosis of Polyploid Cells Regenerates Functional Stem Cells in the Drosophila Intestine

Lucchetta

Ohlstein

2017

Cell Stem Cell

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“…Previous studies have suggested that giant cells have a polyploid [Barlow and Sherman, 1972;Kuhn et al, 1991] or a polytene-like [Brower, 1987;Varmuza et al, 1988] structure. However, there has been no systematic analysis of the DNA in trophoblast giant cells, and it is still controversial whether the cells are polyploid or polytene-like.…”

Section: Introductionmentioning

confidence: 98%

Analysis of CpG islands of trophoblast giant cells by restriction landmark genomic scanning

et al. 1998

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“…not possible from previous cytological studies to ascertain gene copy number with certainty or to survey the entire euchromatic genome, and results yielded inconsistent conclusions about differential replication (56)(57)(58). TGC chromosomes showed detectable heterochromatin staining and the presence of Barr bodies, but there was no increase in the number and size of heterochromatin blocks with increasing ploidy (15).…”

Section: Discussionmentioning

confidence: 85%

Fundamental differences in endoreplication in mammals and Drosophila revealed by analysis of endocycling and endomitotic cells

Sher

Stetina

Bell

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Throughout the plant and animal kingdoms specific cell types become polyploid, increasing their DNA content to attain a large cell size. In mammals, megakaryocytes (MKs) become polyploid before fragmenting into platelets. The mammalian trophoblast giant cells (TGCs) exploit their size to form a barrier between the maternal and embryonic tissues. The mechanism of polyploidization has been investigated extensively in Drosophila , in which a modified cell cycle—the endocycle, consisting solely of alternating S and gap phases—produces polyploid tissues. During S phase in the Drosophila endocycle, heterochromatin and specific euchromatic regions are underreplicated and reduced in copy number. Here we investigate the properties of polyploidization in murine MKs and TGCs. We induced differentiation of primary MKs and directly microdissected TGCs from embryonic day 9.5 implantation sites. The copy number across the genome was analyzed by array-based comparative genome hybridization. In striking contrast to Drosophila , the genome was uniformly and integrally duplicated in both MKs and TGCs. This was true even for heterochromatic regions analyzed by quantitative PCR. Underreplication of specific regions in polyploid cells is proposed to be due to a slower S phase, resulting from low expression of S-phase genes, causing failure to duplicate late replicating genomic intervals. We defined the transcriptome of TGCs and found robust expression of S-phase genes. Similarly, S-phase gene expression is not repressed in MKs, providing an explanation for the distinct endoreplication parameters compared with Drosophila . Consistent with TGCs endocycling rather than undergoing endomitosis, they have low expression of M-phase genes.

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Amitosis and endocycles in early cultured mouse trophoblast

Cited by 25 publications

References 20 publications

Amitosis of Polyploid Cells Regenerates Functional Stem Cells in the Drosophila Intestine

Amitosis of Polyploid Cells Regenerates Functional Stem Cells in the Drosophila Intestine

Analysis of CpG islands of trophoblast giant cells by restriction landmark genomic scanning

Fundamental differences in endoreplication in mammals and Drosophila revealed by analysis of endocycling and endomitotic cells

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