|
|
|
|
|
|
|
||
§
* Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California 94720; and We have analyzed the progressive changes in
the spatial distribution of telomeres during meiosis using three-dimensional, high resolution fluorescence microscopy. Fixed meiotic cells of maize (Zea mays L.)
were subjected to in situ hybridization under conditions
that preserved chromosome structure, allowing identification of stage-dependent changes in telomere arrangements. We found that nuclei at the last somatic
prophase before meiosis exhibit a nonrandom, polarized chromosome organization resulting in a loose
grouping of telomeres. Quantitative measurements on
the spatial arrangements of telomeres revealed that, as
cells passed through premeiotic interphase and into
leptotene, there was an increase in the frequency of
large telomere-to-telomere distances and a decrease in
the bias toward peripheral localization of telomeres. By
leptotene, there was no obvious evidence of telomere
grouping, and the large, singular nucleolus was internally located, nearly concentric with the nucleus. At the
end of leptotene, telomeres clustered de novo at the nuclear periphery, coincident with a displacement of the
nucleolus to one side. The telomere cluster persisted
throughout zygotene and into early pachytene. The nucleolus was adjacent to the cluster at zygotene. At the
pachytene stage, telomeres rearranged again by dispersing throughout the nuclear periphery. The stagedependent changes in telomere arrangements are suggestive of specific, active telomere-associated motility processes with meiotic functions. Thus, the formation
of the cluster itself is an early event in the nuclear reorganizations associated with meiosis and may reflect a
control point in the initiation of synapsis or crossing
over.
Department
of Biochemistry and Biophysics, § Howard Hughes Medical Institute, University of California at San Francisco, San Francisco,
California 94143
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
