Telomere-Led Premeiotic Chromosome Movement in Fission Yeast

Abstract

The movement of chromosomes that precedes meiosis was observed in living cells of fission yeast by fluorescence microscopy. Further analysis by in situ hybridization revealed that the telomeres remain clustered at the leading end of premeiotic chromosome movement, unlike mitotic chromosome movement in which the centromere leads. Once meiotic chromosome segregation starts, however, centromeres resume the leading position in chromosome movement, as they do in mitosis. Although the movement of the telomere first has not been observed before, the clustering of telomeres is reminiscent of the bouquet structure of meiotic-prophase chromosomes observed in higher eukaryotes, which suggests that telomeres perform specific functions required for premeiotic chromosomal events generally in eukaryotes.

pkl1+andklp2+: Two Kinesins of the Kar3 Subfamily in Fission Yeast Perform Different Functions in Both Mitosis and Meiosis

“…Also, microscopy of zygotes formed early in the cross of klp2⌬,dhc1-d1 with itself, with the use of either DAPI to visualize the nuclei or strains carrying Cut11p-GFP to mark the nuclear envelopes (West et al, 1998) revealed that zygotes with a single nucleus were rare in this cross. Most contained two nuclei whose morphology resembled that of diploid nuclei during the "horsetailing" motions of meiotic prophase ( Figure 4C; Chikashige et al, 1994). This is in contrast to the nuclear morphology when dhc1-d1 is crossed with itself.…”

“…A nuclear localization of Klp2p-GFP during mitosis has been confirmed by counterstaining live cells with the vital DNA dye, Hoechst's 33342 (Chikashige et al, 1994). As the cells enter mitosis, the cytoplasmic dots gradually disappear, although an occasional cytoplasmic dot can be seen in a cell with condensed DNA.…”

Meiotic behaviours of chromosomes and microtubules in budding yeast: relocalization of centromeres and telomeres during meiotic prophase

“…The fission yeast S. pombe has provided a convenient experimental system in which to study chromosome dynamics during meiosis. In S. pombe, the continuous observation of chromosomes in living cells has demonstrated that the whole nucleus exhibits an oscillatory movement between the cell poles during the meiotic prophase; a further analysis in fixed cells revealed that telomeres remain clustered at the leading edge of the nuclear movement (Chikashige et al 1994). The universality of the clustering of telomeres during the meiotic prophase has been confirmed in recent studies of nuclear organization in several evolutionally distant organisms; mouse, human and maize (Bass et al 1997).…”

Reconstruction of the Kinetochore during Meiosis in Fission Yeast Schizosaccharomyces pombe

“…pombe provides a useful experimental system in which to study the reorganization of chromosomes during meiosis. In this organism, the centromeres cluster near the spindle pole body (SPB; a centrosome-equivalent structure in fungi) throughout mitotic interphase; however, during meiotic prophase centromeres detach from the SPB, and instead telomeres cluster to the SPB (Chikashige et al, 1994). During this period of meiosis, the nucleus elongates and oscillates between the cell poles, with telomeres clustered at the SPB located at the leading edge of the moving nucleus.…”