Frequencies of coincident genetic events were measured in strain D7 of Saccharomyces cerevisiae. This diploid strain permits the detection of mitotic gene conversion involving the trp5-12 and trp5-27 alleles, mitotic crossing-over and gene conversion leading to the expression of the ade2-40 and ade2-119 alleles as red and pink colonies, and reversion of the ilv1-92 allele. The three genes are on different chromosomes, and one might expect that coincident (simultaneous) genetic alterations at two loci would occur at frequencies predicted by those of the single alterations acting as independent events. Contrary to this expectation, we observed that ade2 recombinants induced by bleomycin, beta-propiolactone, and ultraviolet radiation occur more frequently among trp5 convertants than among total colonies. This excess among trp5 recombinants indicates that double recombinants are more common than expected for independent events. No similar enrichment was found among Ilv(+) revertants. The possibility of an artifact in which haploid yeasts that mimic mitotic recombinants are generated by a low frequency of cryptic meiosis has been excluded. Several hypotheses that can explain the elevated incidence of coincident mitotic recombination have been evaluated, but the cause remains uncertain. Most evidence suggests that the excess is ascribable to a subset of the population being in a recombination-prone state.
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http://dx.doi.org/10.1016/j.mrfmmm.2006.11.014 | DOI Listing |
Nat Commun
January 2025
Department and Graduate Institute of Pharmacology, National Taiwan University College of Medicine, Taipei, Taiwan, ROC.
Adult human hearts exhibit limited regenerative capacity. Post-injury cardiomyocyte (CM) loss can lead to myocardial dysfunction and failure. Although neonatal mammalian hearts can regenerate, the underlying molecular mechanisms remain elusive.
View Article and Find Full Text PDFCells Dev
January 2025
Université Paris-Saclay, Hôpital Kremlin Bicêtre, U1195, Inserm, 94276 Le Kremlin Bicêtre, France. Electronic address:
The temporal control of mitotic exit of individual Schwann cells (SCs) is essential for radial sorting and peripheral myelination. However, it remains unknown when, during their multiple rounds of division, SCs initiate myelin signaling in vivo. By manipulating SC division during development, we report that when SCs skip their division during migration, but not during radial sorting, they fail to myelinate peripheral axons.
View Article and Find Full Text PDFNat Genet
September 2024
Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.
Few transcription factors have been examined for their direct roles in physically connecting enhancers and promoters. Here acute degradation of Yin Yang 1 (YY1) in erythroid cells revealed its requirement for the maintenance of numerous enhancer-promoter loops, but not compartments or domains. Despite its reported ability to interact with cohesin, the formation of YY1-dependent enhancer-promoter loops does not involve stalling of cohesin-mediated loop extrusion.
View Article and Find Full Text PDFJ Phycol
October 2024
Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science and University of Maryland Baltimore County, Baltimore, Maryland, USA.
Haematococcus pluvialis has been used to produce the ketocarotenoid antioxidant, astaxanthin. Currently, heterotrophic cultivation of H. pluvialis is limited by slow growth rates.
View Article and Find Full Text PDFbioRxiv
March 2024
Genetics and Biochemistry Branch, NIDDK, National Institutes of Health, Bethesda, MD, USA.
When germ cells transition from the mitotic cycle into meiotic prophase I (MPI), chromosomes condense into an array of chromatin loops that are required to promote homolog pairing and genetic recombination. To identify the changes in chromosomal conformation, we isolated nuclei on a trajectory from spermatogonia to the end of MPI. At each stage along this trajectory, we built genomic interaction maps with the highest temporal and spatial resolution to date.
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