W. Bruce Currie - Stephen H. Weiss Presidential Fellow Professor
PhD from Macquarie University (Australia)
Graduate fields: Animal Science, Physiology
Area(s) of interest: animal physiology, reproduction, endocrinology
Teaching:
Email: wbc1@cornell.edu
Current Research
In recent years, research has concentrated on problems of early pregnancy that underlie reproductive inefficiencies in farm animals. Most work has involved changes in oocytes between the germinal vesicle stage and the fully matured MII oocyte. A key advantage for much of our work is the availability of hundreds to thousands of bovine oocytes each week from the ovaries of slaughtered cattle. This permits large-scale studies involving in vitro maturation.
Advances in early developmental biology and regulation of cell cycles in various model systems provide leads for studying the dynamics and control of similar processes in bovine oocytes and embryos. We have mapped the early cell cycles in cattle and determined that the early cell cycles lack G1-phases. The substantial attrition that occurs in all cleavage divisions of IVF-derived bovine embryos seems to reflect a failure to pass the G2/M checkpoint, a regulatory point in all mammalian cell cycles that absolutely requires de novo synthesis of a cyclin protein. Early embryonic development depends upon transcripts vested in the oocyte (the so-called maternal pool of mRNA) because major expression off the embryonic genome (the Maternal Zygotic Transition, MZT) does not occur until the 8- to 16-cell stage in cattle.
A current focus of the research is examining the mechanisms that permit recruitment of specific transcripts from the maternal pool of mRNA and the basis for meiotic arrest and then the resumption of meiosis in the GV-stage oocyte. We are also attempting to map the transcriptome of these oocytes.
A recent effort is aimed at establishing methodology for large-scale multi-locus hybridizations to examine between-animal variation in bovine genomic DNA.