Disease relevance of Chromosome Pairing

• E. coli RecA protein promotes homologous pairing in two distinguishable phases: synapsis and strand exchange [1].
• These sites lie in between the core and arm sites recognized by (Tn916)Int, suggesting that the (Tn916)Xis protein enhances excision in a manner similar to the excisionase protein of bacteriophage lambda, serving an architectural role in the stabilization of protein-nucleic acid structures required for strand synapsis [2].

Psychiatry related information on Chromosome Pairing

• Results are consistent with the idea that a dopaminergic D2 synapsis participates in the neural network responsible for satiation with ethanol [3].
• alpha-1-Antichymotrypsin polymorphism in the gene promoter region affects survival and synapsis loss in Alzheimer's disease [4].

High impact information on Chromosome Pairing

• In Escherichia coli, at least two groups of proteins, or "recombination machines," can operate independently on broken DNA to produce a 3'-terminated single-stranded DNA filament coated with RecA protein and ready for synapsis with intact homologous DNA [5].
• In Saccharomyces cerevisiae, meiotic recombination is initiated by Spo11-dependent double-strand breaks (DSBs), a process that precedes homologous synapsis [6].
• We speculate that Zip3 is a component of recombination nodules and serves to link the initiation of synapsis to meiotic recombination [7].
• However, homologous synapsis is independent of recombination in the nematode, since it occurs normally in a C. elegans spo-11 null mutant [8].
• Here, we examine whether this mechanism for initiating meiotic recombination is conserved, and we test the dependence of homologous chromosome synapsis on recombination in C. elegans [8].

Biological context of Chromosome Pairing

• Analysis of axial element and synaptonemal complex formation during prophase of meiosis I indicates abnormalities in chromosome synapsis [9].
• The meiotic checkpoint monitoring synapsis eliminates spermatocytes via p53-independent apoptosis [10].
• Close, stable homolog juxtaposition during meiosis in budding yeast is dependent on meiotic recombination, occurs independently of synapsis, and is distinct from DSB-independent pairing contacts [11].
• Results presented here demonstrate that the dmc1 and rad51 mutants undergo nearly complete chromosome synapsis, but synaptonemal complex formation is delayed substantially compared with wild type [12].
• To gain insight into the molecular interactions responsible for DNA synapsis, the base-pairing status within the synaptic complex was analyzed by using dimethylsulfate and potassium permanganate as probes [13].

Anatomical context of Chromosome Pairing

• Furthermore, detailed cytological examination revealed that chromosomes in cytochalasin-treated oocytes were monovalent while those treated only with cycloheximide were divalent, suggesting that dissociation of the synapsis is a prerequisite for chromosome decondensation after the disappearance of MPF [14].
• Between Days 11 and 16 post-injection we prepared one testis for immunocytological and the other for histological evaluation, then used antibodies to SCP3 and either RPA, or MLH1 to follow quantitative changes in synapsis and recombination [15].
• Presence of ST1 in males is not associated with any compromise in the output of the seminiferous epithelium nor with histological or immunocytochemical evidence of increased apoptosis, outcomes predicted for a synapsis checkpoint [16].
• Furthermore, most, if not all, of the GABA-labeled axon terminals formed symmetric synapsis [17].
• The following gradient of damaging influence of guanethidine was revealed: sympathetic gnl. cervicothoracicum neurocytes gnl. nodosum afferent neurocytes-neuromuscular synapsis skeletal muscle [18].

Associations of Chromosome Pairing with chemical compounds

• Cisplatin-induced DSBs restored Rad51/Dmc1 foci and promoted synapsis [19].
• Conditions that are suboptimal for the formation of the RecA presynaptic filament rendered both the formation of RecA-DNA networks and the subsequent formation of joint molecules sensitive to inhibition by excess ATP or by pyrophosphate when these were added during synapsis [20].
• EphB1 is a member of the Eph family of receptor tyrosine kinases that play important roles in diverse biological processes including nervous system development, angiogenesis, and neural synapsis formation and maturation [21].
• In addition, polyvinyl alcohol and polyethylene glycol must also affect another property of recA protein, i.e. self-association, which is required for synapsis and DNA strand exchange [22].
• We wished to test whether a different, and more stable, synapsis might be achieved if one of the two strands in the synapsable duplex had its domain of guanine residues in a reverse orientation to the rest of the strand, via 5'-5' and 3'-3' linkages [23].

Gene context of Chromosome Pairing

• Dmc1 and, by inference, Rad51 form complexes before synapsis as monitored by immunostaining for Zip1 protein [24].
• Furthermore, unlike Drosophila and Caenorhabditis elegans, but like fungi, SPO11 is necessary for normal synapsis in plants [25].
• Meiotic segregation, synapsis, and recombination checkpoint functions require physical interaction between the chromosomal proteins Red1p and Hop1p [26].
• Moreover, the ability of the yeast SEP1 gene product to cleave DNA in a G4-DNA-dependent fashion, as well as that of the SGS1 gene product to unwind G4 DNA, has suggested a crucial role for this structure in meiotic synapsis and recombination [27].
• MEI4, a meiosis-specific yeast gene required for chromosome synapsis [28].

Analytical, diagnostic and therapeutic context of Chromosome Pairing

• Two-colour immunofluorescence of Cor1 and Syn1 demonstrates that synapsis between homologous cores is initiated at few sites but advances rapidly relative to the establishment of new initiation sites [29].
• The decrease of meiotic exchanges (crossing over and conversion) in two mutants of Sordaria macrospora correlated strongly with a reduction of chiasmata and of both types of "recombination nodules." Serial section reconstruction electron microscopy was used to compare the synapsis pattern of meiotic prophase I in wild type and mutants [30].

References