The distribution of synaptonemal complex material in metaphase I bivalents of Locusta and Chloealtis (Orthoptera: Acrididae)

Møens, Peter B.; Church, Kathleen

doi:10.1007/bf00331575

Cited by 43 publications

(13 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous studies have shown that the elements of the SC can be transformed into a variety of structures that may remain associated to chromosomes until anaphase I [60,61]. Furthermore, in vitro experiments have shown that both SYCP3 and SYCP1 are able to self assemble into filaments and polycomplex-like structures, respectively [62,63].…”

Section: Sycp3 Is Involved In Maintaining the Association Of The Sex mentioning

confidence: 99%

Meiotic pairing and segregation of achiasmate sex chromosomes in eutherian mammals: the role of SYCP3 protein

et al. 2005

View full text Add to dashboard Cite

In most eutherian mammals, sex chromosomes synapse and recombine during male meiosis in a small region called pseudoautosomal region. However in some species sex chromosomes do not synapse, and how these chromosomes manage to ensure their proper segregation is under discussion. Here we present a study of the meiotic structure and behavior of sex chromosomes in one of these species, the Mongolian gerbil (Meriones unguiculatus). We have analyzed the location of synaptonemal complex (SC) proteins SYCP1 and SYCP3, as well as three proteins involved in the process of meiotic recombination (RAD51, MLH1, and c-H2AX). Our results show that although X and Y chromosomes are associated at pachytene and form a sex body, their axial elements (AEs) do not contact, and they never assemble a SC central element. Furthermore, MLH1 is not detected on the AEs of the sex chromosomes, indicating the absence of reciprocal recombination. At diplotene the organization of sex chromosomes changes strikingly, their AEs associate end to end, and SYCP3 forms an intricate network that occupies the Y chromosome and the distal region of the X chromosome long arm. Both the association of sex chromosomes and the SYCP3 structure are maintained until metaphase I. In anaphase I sex chromosomes migrate to opposite poles, but SYCP3 filaments connecting both chromosomes are observed. Hence, one can assume that SYCP3 modifications detected from diplotene onwards are correlated with the maintenance of sex chromosome association. These results demonstrate that some components of the SC may participate in the segregation of achiasmate sex chromosomes in eutherian mammals.

show abstract

Section: Sycp3 Is Involved In Maintaining the Association Of The Sex mentioning

confidence: 99%

Meiotic pairing and segregation of achiasmate sex chromosomes in eutherian mammals: the role of SYCP3 protein

et al. 2005

View full text Add to dashboard Cite

show abstract

“…The observation of retained synaptonemal complex fragments in metaphase I bivalents of the grasshoppers (17,52,55), the pigeon (59) and human spermatocytes (67,75) is more difficult to interpret. The fragments may represent auxiliary chiasma structures (32) equivalent to the circular component of Bombyx spermatocytes or may serve as an additional safety device which, in combination with chromatin chiasmata originating from exchange of nonsister chromatids, ensure a regular disjunction.…”

Section: Chiasmatamentioning

confidence: 99%

“…The fragments may represent auxiliary chiasma structures (32) equivalent to the circular component of Bombyx spermatocytes or may serve as an additional safety device which, in combination with chromatin chiasmata originating from exchange of nonsister chromatids, ensure a regular disjunction. Finally, MOENS (53) and MoENs and CHURCH (55) proposed that such remnants serve in chiasma maintenance by holding together the sister chromatids. Evidently, more work involving reconstructions of nuclei from the stages between late pachytene and metaphase I is required before definite conclusions can be made concerning the significance of the synaptonemal complex fragments in these organisms.…”

Section: Chiasmatamentioning

confidence: 99%

Chromosome pairing, recombination nodules and chiasma formation in diploid Bombyx males

Holm

Rasmussen

1980

Carlsberg Res. Commun.

View full text Add to dashboard Cite

Serial sectioning and three dimensional reconstruction of 82 nuclei divided into 15 well characterized substages covering the period from early zygotene to metaphase I in diploid Bombyx spermatocytes have permitted the following observations and conclusions: 1) At late zygotene, a mean of four chromosome and bivalent interlockings was found per nucleus. 2) During the transition from zygotene to pachytene, all interlockings resolve by breakage and reunion Of chromosomes or bivalents. 3) Recombination nodules first appear at early zygotene, reach a maximum of 91 per nucleus by late zygotene, decrease to 55 per nucleus at mid pachytene and increase again to 70-75 towards the end of pachytene. 4) At late z~cgotene and pachytene, nodules are essentially distributed at random among bivalents as well as along bivalents. 5) Small, but important deviations from randomness were, however, revealed: Three percent of the bivalents were without nodules at late zygotene, 8 % at early pachytene but at mid and late pachytene, only 2 % were devoid of nodules. 6) From mid pachytene, an increasing fraction of the recombination nodules becomes larger and more irregular in shape. These are termed chromatin nodules and at the pachytene-diplotene transition, nearly all nodules are of this type. 7) During early diplotene, the bulk of the chromatin decondenses leaving only about 60 major condensed domains. These domains originate from chromatin nodules and are frequently associated with a piece of synaptonemal complex which in its central region contains a dense core resembling a recombination nodule. 8) At late diplotene, the condensed domains of the bivalents consist of two dense chromatin segments, one on each of the homologues, and bridged by a complex circular structure giving the regions a characteristic tripartite appearance. 9) At mid diakinesis, the circular structures are located in chromatin bridges -chiasmata -between the homologous chromosomes. 10) The number of chiasmata per nucleus is constant from mid diplotene to mid diakinesis and is distributed among the bivalents similar to the distribution of recombination nodules at mid and late pachytene. 11) The circular chiasma components are eliminated from late diakinesis until metaphase I. 12) Finally, each metaphase I bivalent contains four distinct localized centromeres, two by two facing opposite spindle poles. 485

show abstract

“…Grasshopper species follow this last kind of behaviour . In this sense, two elegant ultrastructural studies reported that patches of PSCs appeared between the sister chromatids of grasshopper metaphase I bivalents (Esponda and Krimer 1979;Moens and Church 1979). Thus, although it is clear that in grasshoppers the chromatid cores are not related to the SC as a tripartite structure, the behaviour of SCs elements during post-pachytene stages, and the appearance of silver-stained chromatid cores from diakinesis on, led to the proposal of a model whereby the closely associated cores of both sister chromatids could act as a framework for the addition of specific LE proteins (Fig.…”

Section: Relationship Between Chromatid Cores and Lateral Elementsmentioning

confidence: 98%

Chromatid Cores in Meiotic Chromosome Structure and Segregation

Suja

Rufas

Recombination and Meiosis

View full text Add to dashboard Cite

There is an extensive literature concerning the structure of mitotic chromosomes and the participation of proteinaceous axial structures, the chromatid cores, in their organization. However, the involvement of the chromatid cores in the structure and segregation of meiotic chromosomes is less known. This chapter reviews the occurrence and behaviour of the chromatid cores in condensed meiotic chromosomes, particularly in grasshopper species. We present current models that relate chromatid cores with the lateral elements of the synaptonemal complex, a tripartite structure present along synapsed homologues during the pachytene stage of prophase I. Additionally, we summarize recent data about the relationship between the chromatid cores, DNA topoisomerase IIα, condensin and cohesin complexes.

show abstract

The distribution of synaptonemal complex material in metaphase I bivalents of Locusta and Chloealtis (Orthoptera: Acrididae)

Cited by 43 publications

References 18 publications

Meiotic pairing and segregation of achiasmate sex chromosomes in eutherian mammals: the role of SYCP3 protein

Meiotic pairing and segregation of achiasmate sex chromosomes in eutherian mammals: the role of SYCP3 protein

Chromosome pairing, recombination nodules and chiasma formation in diploid Bombyx males

Chromatid Cores in Meiotic Chromosome Structure and Segregation

Contact Info

Product

Resources

About