نتایج جستجو برای: synapsis
تعداد نتایج: 898 فیلتر نتایج به سال:
چکیده ندارد.
Three-dimensional light microscopy and the excellent cytological features of maize meiotic chromosomes are used to analyze the early events of chromosome synapsis. We demonstrate that the chromosomes undergo a dramatic structural reorganization prior to synapsis in zygotene. The unique features of prezygotene chromosomes are a partial separation of sister chromatids, an elongation of knob heter...
Members of the mammalian mismatch repair protein family of MutS and MutL homologs have been implicated in postreplicative mismatch correction and chromosome interactions during meiotic recombination. Here we demonstrate that mice carrying a disruption in MutS homolog Msh5 show a meiotic defect, leading to male and female sterility. Histological and cytological examination of prophase I stages i...
Using gene targeting in embryonic stem cells, we have derived mice with a null mutation in a DNA mismatch repair gene homolog, PMS2. We observed microsatellite instability in the male germline, in tail, and in tumor DNA of PMS2-deficient animals. We therefore conclude that PMS2 is involved in DNA mismatch repair in a variety of tissues. PMS2-deficient animals appear prone to sarcomas and lympho...
Transposition is one of the primary mechanisms causing genome instability. This phenomenon is mechanistically related to other DNA rearrangements such as V(D)J recombination and retroviral DNA integration. In the Tn5 system, only one protein, the transposase (Tnp), is required for all of the catalytic steps involved in transposon movement. The complexity involved in moving multiple DNA strands ...
The intimate synapsis of homologous chromosome pairs (homologs) by synaptonemal complexes (SCs) is an essential feature of meiosis. In many organisms, synapsis and homologous recombination are interdependent: recombination promotes SC formation and SCs are required for crossing-over. Moreover, several studies indicate that initiation of SC assembly occurs at sites where crossovers will subseque...
Faithful chromosome segregation during meiosis requires that homologous chromosomes associate and recombine. Chiasmata, the cytological manifestation of recombination, provide the physical link that holds the homologs together as a pair, facilitating their orientation on the spindle at meiosis I. Formation of most crossover (CO) events requires the assistance of a group of proteins collectively...
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