Molecular Regulation of the Mitosis/Meiosis Decision in Multicellular Organisms

Kimble, Judith

doi:10.1101/cshperspect.a002683

Cited by 86 publications

(97 citation statements)

References 100 publications

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“…Nutrient limitation has been shown to interfere with meiotic protein initiation and formation in yeast species, Schizosaccharomyces pombe and Saccharomyces cerevisiae (Kimble, 2011). The range of environmental treatments we used was conservative in its application, ensuring that plants would flower, and hence the effect of severe adverse environments may have been underestimated, although purple discoloration of leaves was observed in nutrient-limited plants.…”

Section: Environmental Effectsmentioning

confidence: 97%

“…This approach has been used extensively by potato breeders to produce and introgress desirable genes from diploid into tetraploid lineages (Dewitte et al, 2012). Although less intensively studied, nutrient deficiency has also been shown to delay or interfere with formation of integral proteins involved with meiosis initiation (Kimble, 2011) and has been implicated in increased unreduced gamete production (Grant, 1952). Herbivory has also been associated with elevated rates of unreduced gametes when direct floral damage occurs (Kostoff andKendall, 1929, 1930;Kostoff, 1933) but the effects of herbivory on unreduced gamete production have received little or no attention since these early studies.…”

Section: Introductionmentioning

confidence: 99%

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Genetic and environmental determinants of unreduced gamete production in Brassica napus, Sinapis arvensis and their hybrids

2016

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Unreduced gametes, sperm or egg cells with the somatic chromosome number, are an important mechanism of polyploid formation and gene flow between heteroploid plants. The meiotic processes leading to unreduced gamete formation are well documented, but the relative influence of environmental and genetic factors on the frequency of unreduced gametes remain largely untested. Furthermore, direct estimates of unreduced gametes based on DNA content are technically challenging and, hence, uncommon. Here, we use flow cytometry to measure the contribution of genetic (hybridization) and environmental (nutrient limitation, wounding) changes to unreduced male gamete production in Brassica napus, Sinapis arvensis and two hybrid lines. Treatments were applied to greenhouse grown plants in a random factorial design, with pollen sampled at two time intervals. Overall, the frequency of unreduced gametes averaged 0.59% (range 0.06-2.17%), plus a single outlier with 27%. Backcrossed hybrids had 39 to 75% higher unreduced gamete production than parental genotypes, averaged across all treatments, although the statistical significance of these differences depended on sampling period and wounding treatment. Unreduced gamete frequencies were higher for the second sampling period than the first. There were no direct effects of wounding or nutrient regime. Our results indicate that both genetic and environmental factors can induce increased unreduced gametes, highlighting the potential importance of environmental heterogeneity and genetic composition of populations in driving polyploid evolution.

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Section: Environmental Effectsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Genetic and environmental determinants of unreduced gamete production in Brassica napus, Sinapis arvensis and their hybrids

2016

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“…Post-transcriptional control of gene expression is common in the germline, where protein expression patterns are often determined by RNA-binding proteins that bind to sequences in the 3Ј UTR (reviewed by Rangan et al, 2008;Kimble, 2011;Voronina et al, 2011). Germ cells contain a unique type of RNA granule, or 'nuage', that localizes to the cytoplasmic face of the nuclear envelope.…”

Section: Introductionmentioning

confidence: 99%

The P granule component PGL-1 promotes the localization and silencing activity of the PUF protein FBF-2 in germline stem cells

2012

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SUMMARYIn the C. elegans germline, maintenance of undifferentiated stem cells depends on the PUF family RNA-binding proteins FBF-1 and FBF-2. FBF-1 and FBF-2 are 89% identical and are required redundantly to silence the expression of mRNAs that promote meiosis. Here we show that, despite their extensive sequence similarity, FBF-1 and FBF-2 have different effects on target mRNAs. FBF-1 promotes the degradation and/or transport of meiotic mRNAs out of the stem cell region, whereas FBF-2 prevents translation. FBF-2 activity depends on the P granule component PGL-1. PGL-1 is required to localize FBF-2 to perinuclear P granules and for efficient binding of FBF-2 to its mRNA targets. We conclude that multiple regulatory mechanisms converge on meiotic RNAs to ensure silencing in germline stem cells. Our findings also support the view that P granules facilitate mRNA silencing by providing an environment in which translational repressors can encounter their mRNA targets immediately upon exit from the nucleus.

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“…The Caenorhabditis elegans germline is an important model for the study of stem cell biology (Kimble 2011;Hansen and Schedl 2013;Hubbard et al 2013). The adult hermaphrodite germline contains stem cells based on their ability to produce gametes over an extended portion of life span (10 days) (Hughes et al 2007), their ability to regenerate the adult germline following environmental perturbation (Angelo and Van Gilst 2009;Seidel and Kimble 2011), and their multipotency (being able to generate either female or male gametes) (Ellis and Schedl 2007).…”

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confidence: 99%

Analysis of Germline Stem Cell Differentiation Following Loss of GLP-1 Notch Activity in Caenorhabditis elegans

Fox

Schedl

2015

Genetics

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Stem cells generate the differentiated progeny cells of adult tissues. Stem cells in the Caenorhabditis elegans hermaphrodite germline are maintained within a proliferative zone of 230 cells, 20 cell diameters in length, through GLP-1 Notch signaling. The distal tip cell caps the germline and supplies GLP-1-activating ligand, and the distal-most germ cells that occupy this niche are likely self-renewing stem cells with active GLP-1 signaling. As germ cells are displaced from the niche, GLP-1 activity likely decreases, yet mitotically cycling germ cells are found throughout the proliferative zone prior to overt meiotic differentiation. Following loss of GLP-1 activity, it remains unclear whether stem cells undergo transit-amplifying (TA) divisions or more directly enter meiosis. To distinguish between these possibilities we employed a temperature-sensitive (ts) glp-1 mutant to manipulate GLP-1 activity. We characterized proliferative zone dynamics in glp-1(ts) mutants at permissive temperature and then analyzed the kinetics of meiotic entry of proliferative zone cells after loss of GLP-1. We found that entry of proliferative zone cells into meiosis following loss of GLP-1 activity is largely synchronous and independent of their distal-proximal position. Furthermore, the majority of cells complete only a single mitotic division before entering meiosis, independent of their distal-proximal position. We conclude that germ cells do not undergo TA divisions following loss of GLP-1 activity. We present a model for the dynamics of the proliferative zone that utilizes cell cycle rate and proliferative zone size and output and incorporates the more direct meiotic differentiation of germ cells following loss of GLP-1 activity.

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Molecular Regulation of the Mitosis/Meiosis Decision in Multicellular Organisms

Cited by 86 publications

References 100 publications

Genetic and environmental determinants of unreduced gamete production in Brassica napus, Sinapis arvensis and their hybrids

Genetic and environmental determinants of unreduced gamete production in Brassica napus, Sinapis arvensis and their hybrids

The P granule component PGL-1 promotes the localization and silencing activity of the PUF protein FBF-2 in germline stem cells

Analysis of Germline Stem Cell Differentiation Following Loss of GLP-1 Notch Activity in Caenorhabditis elegans

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