Chair: Bob Pruitt, Harvard University
The session began with a talk by Daphne Preuss who described her continuing work on genetic control of the reproductive process. She described the isolation of new mutations which suppress the sterility phenotype of specific cer mutations. In addition, she described a combination of two mutations which produces pollen tubes which are incapable of being correctly guided to the ovules.
The second talk, given by Patty Springer, described the use of a gene trap transposon system to isolate a mutation which affects the development of the female gametophyte as well as the embryo. Cloning of the gene revealed it to have homology with MCM2, MCM3 and MCM5 genes of yeast, genes which are required for the initiation of DNA replication.
Animesh Ray spoke next, describing further work with the bel and sin mutations, as well as the isolation of novel mutations which alter sporophytic or gametophytic tissue development within the ovule.
The fourth talk would have been given by Kay Schneitz who unfortunately missed the session due to a cancelled Swissair flight. Kay was to report on progress to saturate the genome for ovule development mutations, a project begun in the Pruitt lab which is now approaching completion.
The two final talks were chosen from the poster abstracts and were given by David Smyth and Ueli Grossniklaus. David described the crabs claw mutation which results in a failure of the upper part of the gynoecium to fuse properly. The gene has been cloned in David's laboratory and encodes a small protein which appears to have a single zinc finger motif. Ueli Grossniklaus further described the Cold Spring Harbor groups efforts to isolate both gene trap and enhancer trap lines, concentrating on those which are expressed in the developing ovule. Ueli showed micrographs of the expression patterns of a number of lines, including ones that showed expression which was clearly limited to small regions of the developing sporophytic tissues.