Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comment
. 2020 Oct 1;16(10):e1008997.
doi: 10.1371/journal.pgen.1008997. eCollection 2020 Oct.

How noncrossover homologs are conjoined and segregated in Drosophila male meiosis I: Stable but reversible homolog linkers require a novel Separase target protein

Elsie E Adams  1 , Qiutao He  1 , Bruce D McKee  1   2
Affiliations
Comment

How noncrossover homologs are conjoined and segregated in Drosophila male meiosis I: Stable but reversible homolog linkers require a novel Separase target protein

Elsie E Adams et al. PLoS Genet. .
No abstract available

PubMed Disclaimer

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Two distinct mechanisms for linking homologous chromosomes during meiosis I.
(A) Chiasmata [1]. (Left) Crossovers between non-sister chromatids (blue and red lines) are completed during prophase I. Homologs remain connected by arm cohesion provided by cohesin complexes (gray rings) located distal to sites of crossovers. Other cohesins in pericentromeric regions function to maintain sister chromatid connections until anaphase II. (Right) At metaphase I, spindle fibers (green lines) connect cooriented sister kinetochores (gray ovals) of each homologous centromere (red and blue balls) to opposite spindle poles. Opposing poleward forces (black arrows) exerted on homologous centromeres are resisted by distal arm cohesins, preventing premature separation of homologs and enabling homolog pairs to biorient. At anaphase I, Separase (scissors) cleaves the alpha-kleisin subunits of arm cohesins, dissolving chiasmata and releasing homologs to segregate to opposite poles but leaving pericentromeric cohesion intact until anaphase II. (B) AHC [5]. (Left) In Drosophila male meiosis, homologs replicate and pair but do not undergo crossing over. AHC complexes (depicted as large gray rings for illustration purposes only) composed at least of the SNM, MNM, and UNO proteins, maintain stable connections between achiasmate homologs by an unknown mechanism. (Right) At metaphase I, opposing poleward forces exerted by spindle fibers emanating from opposite poles on homologous centromeres are resisted by AHC complexes, preventing premature separation of homologs and enabling homolog pairs to biorient. At anaphase I, Separase cleaves the UNO subunits of AHC complexes, dissolving conjunction and releasing homologs to segregate to opposite poles but leaving pericentromeric cohesion intact until anaphase II [3]. AHC, alternative homolog conjunction; MNM, mod(mdg4) in meiosis; SNM, stromalin in meiosis; UNO, univalents only.
See this image and copyright information in PMC

Comment on

References

    1. Petronczki M, Siomos MF, Nasmyth K. Un menage a quatre: the molecular biology of chromosome segregation in meiosis. Cell. 2003;112:423–440. - PubMed
    1. Schleiffer A, Kaitna S, Maurer-Stroh S, Glotzer M, Nasmyth K, Eisenhaber F. Kleisins: a superfamily of bacterial and eukaryotic SMC protein partners. Mol Cell. 2003;11:571–575. - PubMed
    1. Weber J, Kabakci Z, Chaurasia S, Brunner E, Lehner CF. Chromosome separation during Drosophila male meiosis I requires separase-mediated cleavage of the homolog conjunction protein UNO. PLoS Genet. 2020. - PMC - PubMed
    1. Wolf KW. How meiotic cells deal with non-exchange chromosomes. Bioessays. 1994;16:107–113. - PubMed
    1. McKee BD, Yan R, Tsai JH. Meiosis in male Drosophila. Spermatogenesis. 2012;2:167–184. 10.4161/spmg.21800 - DOI - PMC - PubMed

Publication types

LinkOut - more resources