Dmc1 fluorescent foci in prophase I nuclei of diploid, triploid and hybrid lilies.
We examined the distribution of meiotic epitopes for the Dmc1 protein of lilies in a normal diploid, a triploid, and in a diploid species-hybrid. The triploid has an extra chromosome set; all three sets align, but only two of the three axes intimately pair at a given location. Our findings with the triploid support the idea that retention of the foci until the pachytene stage requires a successful homology check and synaptonemal complex (SC) initiation; the number of foci in the triploid diminishes by approximately 30% from early zygotene to pachytene, and the triploid pachytene values are similar to the pachytene values of the diploid. The species-hybrid lacks chromosome homology, has reduced SC formation and few reciprocal genetic exchanges. In this species-hybrid the number of foci at early zygotene is similar to that in the normal diploid but is dramatically reduced by mid-zygotene. The extent to which the number of Dmc1 foci is reduced is similar to the extent that SC formation is reduced. In contrast the extent of the reduction in reciprocal genetic exchange in the species-hybrid is much greater than the reduction in the number of foci. We conclude that Dmc1 protein is involved in homology checking, but the impact of failure to find homology affects SC formation and reciprocal genetic exchange differentially.
Division of Life Science, University of Toronto at Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada.
Susan
S
George
Pearl
P
Behl
Rhoda
R
DeGuzman
Marian
M
Lee
Stefan
S
Rusyniak
Yasuo
Y
Hotta
Kazuyuki
K
Hiratsuka
Hisabumi
H
Takase
Clare
C
Hasenkampf
D015153:Blotting, Western; D018797:Cell Cycle Proteins; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005453:Fluorescence; D007150:Immunohistochemistry; D027762:Lilium / Q000235:genetics / Q000378:metabolism*; D011003:Ploidies; D011418:Prophase
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins