Surface spreading of synaptonemal complexes in locusts

Jones, Gareth R.; Croft, J. A.

doi:10.1007/bf00386789

Cited by 26 publications

(9 citation statements)

References 26 publications

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“…The average chiasmata number per bivalent, however, is much lower and hardly varies, at around 1–3 per bivalent (2.45 per bivalent for the lily, for example). Animals have much lower numbers of interstitial pairing sites [42], but even so, the ratio between synapsis initiation sites and chiasmata can be higher than 1 [43]. Lastly, immunocytology studies on mouse showed that in mammals, synapsis can proceed from sites different than CO sites (cited in [14]).…”

Section: Discussionmentioning

confidence: 99%

Zip4/Spo22 Is Required for Class I CO Formation but Not for Synapsis Completion in Arabidopsis thaliana

et al. 2007

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In budding yeast meiosis, the formation of class I interference-sensitive crossovers requires the ZMM proteins. These ZMM proteins are essential in forming a mature synaptonemal complex, and a subset of these (Zip2, Zip3, and Zip4) has been proposed to compose the core of synapsis initiation complexes (SICs). Zip4/Spo22 functions with Zip2 to promote polymerization of Zip1 along chromosomes, making it a crucial SIC component. In higher eukaryotes, synapsis and recombination have often been correlated, but it is totally unknown how these two processes are linked. In this study, we present the characterization of a higher eukaryote SIC component homologue: Arabidopsis AtZIP4. We show that mutations in AtZIP4 belong to the same epistasis group as Atmsh4 and eliminate approximately 85% of crossovers (COs). Furthermore, genetic analyses on two adjacent intervals of Chromosome I established that the remaining COs in Atzip4 do not show interference. Lastly, immunolocalization studies showed that polymerization of the central element of the synaptonemal complex is not affected in Atzip4 background, even if it may proceed from fewer sites compared to wild type. These results reveal that Zip4 function in class I CO formation is conserved from budding yeast to Arabidopsis. On the other hand, and contrary to the situation in yeast, mutation in AtZIP4 does not prevent synapsis, showing that both aspects of the Zip4 function (i.e., class I CO maturation and synapsis) can be uncoupled.

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Section: Discussionmentioning

confidence: 99%

Zip4/Spo22 Is Required for Class I CO Formation but Not for Synapsis Completion in Arabidopsis thaliana

et al. 2007

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“…The occasional occurrence of interstitial SC segments does, however, show that interstitial initiation sites for synapsis exist but are usually not expressed. The existence of up to 7-9 interstitial sites for synaptic initiation per nucleus in Locusta (2n = 22+X) and Schistocerca (2n = 22+X) was inferred from the presence of SC segments (32) and confirmed in Locusta by the occurrence ofquadrivalents with up to two shifts of pairing partner in reconstructed autotetraploid spermatocyte nuclei (S.W. RASMUSSEN, K. CARBONE, L. CARBONE, unpublished observations).…”

Section: Synapsis and Synaptonemai Complex Formationmentioning

confidence: 93%

Initiation of synapsis and interlocking of chromosomes during zygotene in Bombyx spermatocytes

Rasmussen

1986

Carlsberg Res. Commun.

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Keywords: Meiosis, synaptonemal complexInitiation of synapsis and interlocking of chromosomes have been analysed on spread and silver stained chromosome complements from Bombyx spermatocytes. The material comprises 270 zygotene and 125 pachytene nuclei. Two types of associations preceding synaptonemal complex formation were detected: The first type involved short subterminal segments of homologous chromosomes while the second occurred between the telomeric attachment plaques of homologous as well as nonhomologous chromosomes. The possible role of the two types of initial associations in synaptonemal complex formation is discussed.The occurrence and resolution of chromosome interlocking have been monitored during the entire zygotene stage. Interlockings form and resolve throughout zygotene. The estimated mean number ofinterlockings is 4.2 per nucleus at zygotene while only 3 presumptive interlockings were found in 125 pachytene nuclei. In individual zygotene nuclei up to 61% of the chromosomes are affected by interlocking. The mechanism for resolution of interlockings is discussed.

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“…Movement of the telomeres of the homologs to adjacent positions, however, is the consequence rather than the cause of pairing. Terminal initiation of SC formation is usually not at the telomeres, but slightly proximal(Jones and Croft 1986). In inversion heterozygotes, pairing can readily initiate inside the pairing loop, without the possibility of zipping up from either chromosomal end or from the centromere, provided the inversion is situated in a segment where pairing initiation is possible.…”

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confidence: 98%

What makes homologous chromosomes find each other in meiosis? A review and an hypothesis

Sybenga¹

1999

Chromosoma

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The conditions re reviewed that must be met by any model of long distance attraction and transport of homologous chromosomes to the points of intimate DNA synapsis. A proposal for possible mechanisms is presented. It includes transcription and repair factors acting on coding sequences as a preparatory step toward pairing, and the attachment of specific pairing proteins to these sequences. Double-strand break formation is prepared but not immediately completed at the same sites. It is concluded that DNA-DNA interactions cannot bridge the distances between homologous chromosomes in the nucleus, and it is suggested that protein chains are formed between homologous segments. These attach to homologous chains emanating from homologous sequences in other chromosomes, and the chains move along each other until the homologous DNA sequences meet. Then, if required, a synaptonemal complex is formed, and exchange can take place.

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Surface spreading of synaptonemal complexes in locusts

Cited by 26 publications

References 26 publications

Zip4/Spo22 Is Required for Class I CO Formation but Not for Synapsis Completion in Arabidopsis thaliana

Zip4/Spo22 Is Required for Class I CO Formation but Not for Synapsis Completion in Arabidopsis thaliana

Initiation of synapsis and interlocking of chromosomes during zygotene in Bombyx spermatocytes

What makes homologous chromosomes find each other in meiosis? A review and an hypothesis

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