Fig. 5. Deletion of CTF8, CHL1 and CTF4 rescues the nuclear division block of mam1
cells in anaphase I. Diploid mam1
(K8923) (A,B) and mam1
ctf8
(K10572) (D,E) strains expressing Pds1-Myc18 (securin) and carrying one homolog of chromosome V marked by GFP (heterozygous URA3-GFP) were analysed in a meiotic time course. Cells were fixed and stained for DNA and with antibodies against tubulin and the Myc epitope. Fluorescent-microscopy images of securin-positive metaphase I cells with a bipolar spindle (A,D), a securin-negative `abortive' anaphase I (B) and a securin-negative elongated anaphase I (E) are shown. (A,B,D,E) The upper panels show URA3-GFP (green), tubulin (red) and DNA (blue); the lower panels show securin staining (white) of the cells above them. Schematic drawings illustrating an `abortive' anaphase of mam1
cells (C) and the rescued anaphase in mam1
ctf8
cells (F) showing meiotic cohesin in red and URA3-GFP in green. (G) The percentage of nuclear division and spindle elongation in wild-type (K10003), ctf8
(K10576), chl1
(K11652), ctf4
(K11692), mam1
(K8923), mam1
ctf8
(K10572), mam1
chl1
(K11703) and mam1
ctf4
(K11828) cells following the destruction of securin in anaphase I. 100 securin-negative cells with a bipolar metaphase I or anaphase I spindle were scored for each strain in this experiment.