Postdoc: Gene Expression in Maize Sperm

Sheila McCormick sheilamc at
Tue Feb 29 10:48:16 EST 2000

Postdoctoral Research Associate: Isolation and characterization of
sperm-expressed genes and proteins from Zea mays

Despite the crucial role of sperm in fertilization, virtually nothing
is known about sperm cell gene expression, largely because sperm
cells in the quantities necessary for molecular and biochemical
characterization could not be obtained, and because partially
purified sperm cells are often highly contaminated with the
cytoplasm of the vegetative cell. The postdoc will prepare cDNA
libraries from highly  purified maize sperm (available via our
collaboration with the RDP, Lyon, France) and sequence large
numbers of clones, in order to obtain a representation of sperm
-expressed genes. Proteins important for interactions with the
female cells will likely be located on the surface of sperm. To
enrich for genes encoding sperm-surface proteins, the sperm
cDNA library will be cloned into a yeast vector; cDNAs that
encode secreted proteins allow an invertase mutant of yeast to
grow. Once sperm-surface proteins are identified, homologs of
these genes will be obtained via PCR and/or database searches of
other plant genomes. Interspecies sequence comparisons will help
in identifying proteins that have species variability and might
therefore be important in sperm-egg recognition. Selected genes
will be targeted for further analysis. If time permits, the postdoc
will test if recently developed PCR methods can be used to
construct cDNA libraries from small numbers of isolated eggs.
If so, studies parallel to those outlined above will also be
performed with egg cDNA libraries.

Qualifications: Ph.D. in genetics, molecular biology, biochemistry
or related field. Hands-on experience in molecular biology and/or
biochemistry, especially library construction. Experience in
computational analysis is desirable.

Appointment is for two years; salary is $37,744 per year + benefits.
Minority applicants are especially encouraged to apply.
Some limitations on citizenship (see below).

Highly motivated individuals should send their CV, statement of
research interests and a list of 3 references (name and e-mail
address) to:

Dr. Sheila McCormick
Plant Gene Expression Center
800 Buchanan St.
Albany, CA 94710
Telephone: (510) 559-5906
Fax: (510) 559-5678
E-mail: sheilamc at

Note that I will be attending the Maize Meeting (Coeur díAlene, Idaho, March
16-19, 2000) and can discuss the project there.

[Citizenship limitations on this position requires that it be filled by
1) citizens of the United States, 2) a citizen of a country which is a
member of a defense treaty, eg., NATO, SEATO, RIO treaty or 3)
by citizens of countries which the U.S. congress has specifically
exempted from the restricting legislation.
These countries include: Argentina, Australia, Bahamas, Belgium, Bolivia,
Brazil, Canada, Chile, Columbia, Costa Rica, Cuba, Denmark, Dominican
Ecuador, El Salvador, France, Germany, Greece, Guatemala, Haiti, Honduras,
Iceland, Italy, Japan, South Korea, Luxembourg, Mexico, Netherlands, New
Zealand, Nicaragua, Norway, Panama, Paraguay, Peru, Philippines, Portugal,
Spain, Thailand, Tobago, Trinidad, Turkey, United Kingdom, United States,
Uruguay, Venezuela, Ireland, Israel, (South Vietnamese, Cambodian, and Laotian
refugees paroled into the U.S. after January 1, 1975), (Aliens from Cuba,
Poland, South Vietnam, countries of the former Soviet Union, Estonia, Latvia,
and Lithuania admitted to the U.S. for permanent residence), (Natives of Guam,
Puerto Rico, and the Northern Mariana Islands), and (Nationals of the Peoples
Republic of China that were in the U.S. on or before June 5, 1989 up until
April 11, 1990, and qualify under the Chinese student protection act of 1992)]


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