scholarly journals Mammalian Meiotic Telomeres: Protein Composition and Redistribution in Relation to Nuclear Pores

2000 ◽  
Vol 11 (12) ◽  
pp. 4189-4203 ◽  
Author(s):  
Harry Scherthan ◽  
Martin Jerratsch ◽  
Bibo Li ◽  
Susan Smith ◽  
Maj Hultén ◽  
...  
Keyword(s):  
Meiotic Prophase ◽  
Meiotic Chromosome ◽  
Protein Composition ◽  
Structure And Function ◽  
Telomeric Repeat ◽  
Nuclear Pore ◽  
Protective Structure ◽  
Nuclear Pores ◽  
Binding Factor ◽  
And Function

Mammalian telomeres consist of TTAGGG repeats, telomeric repeat binding factor (TRF), and other proteins, resulting in a protective structure at chromosome ends. Although structure and function of the somatic telomeric complex has been elucidated in some detail, the protein composition of mammalian meiotic telomeres is undetermined. Here we show, by indirect immunofluorescence (IF), that the meiotic telomere complex is similar to its somatic counterpart and contains significant amounts of TRF1, TRF2, and hRap1, while tankyrase, a poly-(ADP-ribose)polymerase at somatic telomeres and nuclear pores, forms small signals at ends of human meiotic chromosome cores. Analysis of rodent spermatocytes reveals Trf1 at mouse, TRF2 at rat, and mammalian Rap1 at meiotic telomeres of both rodents. Moreover, we demonstrate that telomere repositioning during meiotic prophase occurs in sectors of the nuclear envelope that are distinct from nuclear pore-dense areas. The latter form during preleptotene/leptotene and are present during entire prophase I.

Impact of non-synonymous mutations on the structure and function of telomeric repeat binding factor 1

2021 ◽  
pp. 1-14
Author(s):  
Insan Habib ◽  
Shama Khan ◽  
Taj Mohammad ◽  
Afzal Hussain ◽  
Mohamed F. Alajmi ◽  
...  
Keyword(s):  
Structure And Function ◽  
Telomeric Repeat ◽  
Synonymous Mutations ◽  
Binding Factor ◽  
And Function

scholarly journals Two structurally distinct domains of the nucleoporin Nup170 cooperate to tether a subset of nucleoporins to nuclear pores

2009 ◽  
Vol 185 (3) ◽  
pp. 387-395 ◽  
Author(s):  
Dirk Flemming ◽  
Phillip Sarges ◽  
Philipp Stelter ◽  
Andrea Hellwig ◽  
Bettina Böttcher ◽  
...  
Keyword(s):  
Pore Structure ◽  
Structure And Function ◽  
Nuclear Pore ◽  
Nuclear Pores ◽  
Terminal Domain ◽  
C Terminus ◽  
N Terminus ◽  
The Individual ◽  
And Function

How individual nucleoporins (Nups) perform their role in nuclear pore structure and function is largely unknown. In this study, we examined the structure of purified Nup170 to obtain clues about its function. We show that Nup170 adopts a crescent moon shape with two structurally distinct and separable domains, a β-propeller N terminus and an α-solenoid C terminus. To address the individual roles of each domain, we expressed these domains separately in yeast. Notably, overexpression of the Nup170 C domain was toxic in nup170Δ cells and caused accumulation of several Nups in cytoplasmic foci. Further experiments indicated that the C-terminal domain anchors Nup170 to nuclear pores, whereas the N-terminal domain functions to recruit or retain a subset of Nups, including Nup159, Nup188, and Pom34, at nuclear pores. We conclude that Nup170 performs its role as a structural adapter between cytoplasmically oriented Nups and the nuclear pore membrane.

Meiotic Chromosome Structure and Function in Plants

2014 ◽  
Vol 143 (1-3) ◽  
pp. 6-17 ◽  
Author(s):  
Samantha Mainiero ◽  
Wojciech P. Pawlowski
Keyword(s):  
Chromosome Structure ◽  
Meiotic Chromosome ◽  
Structure And Function ◽  
And Function

scholarly journals Meiotic condensin is required for proper chromosome compaction, SC assembly, and resolution of recombination-dependent chromosome linkages

2003 ◽  
Vol 163 (5) ◽  
pp. 937-947 ◽  
Author(s):  
Hong-Guo Yu ◽  
Douglas E. Koshland
Keyword(s):  
Mitotic Chromosome ◽  
Chromosome Structure ◽  
Chromosomal Localization ◽  
Meiotic Chromosome ◽  
Chromosome Condensation ◽  
Structure And Function ◽  
Double Strand Breaks ◽  
Strand Breaks ◽  
Evolutionarily Conserved ◽  
And Function

Condensin is an evolutionarily conserved protein complex that helps mediate chromosome condensation and segregation in mitotic cells. Here, we show that condensin has two activities that contribute to meiotic chromosome condensation in Saccharomyces cerevisiae. One activity, common to mitosis, helps mediate axial length compaction. A second activity promotes chromosome individualization with the help of Red1 and Hop1, two meiotic specific components of axial elements. Like Red1 and Hop1, condensin is also required for efficient homologue pairing and proper processing of double strand breaks. Consistent with these functional links condensin is necessary for proper chromosomal localization of Red1 and Hop1 and the subsequent assembly of the synaptonemal complex. Finally, condensin has a Red1/Hop1-independent role in the resolution of recombination-dependent linkages between homologues in meiosis I. The existence of distinct meiotic activities of condensin (axial compaction, individualization, and resolution of recombination-dependent links) provides an important framework to understand condensin's role in both meiotic and mitotic chromosome structure and function.

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