As a faculty member in the Biomedical Sciences department, having an active and viable research group is an important component of my job. Since my postdoctoral years I have been working on the question of how the two genders are produced, wanting to know at the level of molecules how this ‘decision’ is made. About three years ago, we discovered a direct link between the RNA silencing machinery and the master switch that controls the determination of sexual identity in fruit flies. We now want to understand how it is that RNA silencing affects the fruit fly sex determination process. We plan to use this well-established system to understand how RNA silencing regulates and fine-tunes a developmental pathway.
In addition to research, I am involved in teaching graduate-level courses. These are usually team-taught and in molecular biology, biochemistry or genetics. Another major responsibility is to facilitate some of the small-group sessions in Biochemistry, Microbiology, Pharmacology and Physiology for our first- and second-year medical students.
Since March 2010, I also have served as the Assistant Graduate Program director in the Biomedical Sciences department.
Jamila Horabin came to the United States on an International Scholarship to Duke University in Durham, N.C. After getting her bachelor's degree, she stayed on at Duke for her Ph.D. Courses during the graduate years made a lasting impression of the idea that development could be understood at the level of molecules. Toward this goal, she decided to work on Drosophila as the model system.
B.A., Duke University. Major: Chemistry. Summa Cum Laude. (1981)
Ph.D, Duke University. Major: Biochemistry, Genetics. Supervisor: Robert Webster, Ph.D.(1987)
Postdoctoral training, Department of Molecular Biology, Princeton University, Princeton, N.J. Mentor: Paul Schedl, Ph.D. (1988–1993)
FSU University Committees
Member, Graduate Policy Committee (2009–2011).
FSU College Committees
Member, COM Liaison Committee on Medical Education Accreditation, Faculty Subcommittee (2010–2011).
Member, COM Medical Student Admissions Committee (2006–present).
FSU Department Committees
Member, Faculty Search Committee (2009).
Member, Graduate Program Committee (2009–2010).
Member, Faculty Evaluation Committee (2009).
Chair, Graduate Admissions Committee (2008).
Member, Faculty Development Committee (2005).
Elected member, Faculty Tenure Committee (2005).
Member, Graduate Program Committee (2005).
Member, Graduate Curriculum Committee (2005–2007).
FSU Program Committees
Assistant Director, Graduate Program, Biomedical Sciences Department, College of Medicine (2010–present).
Outstanding Senior Faculty Researcher, FSU College of Medicine (2011).
Honor Roll Award, American Cancer Society (2001).
Phi Beta Kappa, Duke University (1981).
Graduate Scholarship (1981).
Cranmer Memorial Scholarship (1980).
Class Honors (1980).
Phi Lambda Upsilon (1980).
Phi Eta Sigma, Freshman Honor Society (1979).
Duke International Scholar, Duke University (1978).
Genetics Society of America.
Association of American Medical Colleges.
Our research uses the model system Drosophila melanogaster and studies the process of sex determination. Much of our work has revolved around understanding the regulation of expression of the sex-determination master switch gene, Sex-lethal (Sxl), as its expression determines female identity while male development is the default. Over the years, we have contributed toward understanding how:
• Regulated splicing of Sxl mRNA occurs.
• Sxl protein functions to generate sexually dimorphic body size.
• Early X chromosome gene dose expression affects the sex determination process.
Current research in the lab is aimed at understanding the role of the RNA silencing machinery in the process of sex determination. Females show a greater need than males for RNA silencing components, to robustly determine their sex. We hope to learn more about RNA silencing using sex determination as the readout, placing our understanding in the context of a developmental process. Our research is funded by NIH.
Horabin, J. I. (in press). Balancing sex chromosone expression and satisfying the sexes. Fly.
Kappes, G., Deshpande, G., Mulvey, B. B., Horabin, J. I., & Schedl, P. (2011). The Drosophila Myc gene, diminutive, is a positive regulator of the Sex-lethal establishment promoter, Sxl-Pe. Proc Natl Acad Sci U S A, 108(4), 1543-8.
Proceedings of the National Academy of Sciences of the United States of America Kappes, Gretchen hpande, Girish vey, Brett B abin, Jamila I edl, Paul 43432/GM/NIGMS NIH HHS/ 85165/GM/NIGMS NIH HHS/ c Natl Acad Sci U S A. 2011 Jan 25;108(4):1543-8. Epub 2011 Jan 10.
Li, H., Rodriguez, J., Yoo, Y., Shareef, M. M., Badugu, R., Horabin, J. I., & Kellum, R. (2011). Cooperative and antagonistic contributions of two heterochromatin proteins to transcriptional regulation of the Drosophila sex determination decision. PLoS Genet, 7(6), e1002122.
PLoS genetics Li, Hui riguez, Janel , Youngdong reef, Momin Mohammed ugu, Ramakrishna abin, Jamila I lum, Rebecca S Genet. 2011 Jun;7(6):e1002122. Epub 2011 Jun 9. Journal Impact Factor: 8.7.
Horabin, J. I., Kleinman, E., Olcese, U., Martin, C. T., & Rodriguez, J. Effects on Drosophila sex determination by Dicer-2 suggest a role in transcription and chromatin formation that is independent of endogenous siRNA production. (submitted 2010).
Li, H., Rodriguez, J., Yoo, Y., Shareef, M., Badugu, R., Horabin, J. I., & Kellum, R. Cooperative and antagonistic roles of heterochromatin proteins in transcriptional regulation of the Drosophila sex determination masterswitch. (submitted 2010). PLoS Genetics.
Gladstein, N., McKeon, M. N., & Horabin, J. I. (2010). Requirement of male-specific dosage compensation in Drosophila females – implications of early X chromosome gene expression. PLoS Genetics, 6 (7), e1001041.
Walthall, S. L., Moses, M., & Horabin, J. I. (2007). A large complex with both Patched and Smoothened initiates Hedgehog signaling in Drosophila. J. Cell Science, 120, 826-837.
Horabin, J. I. (2005). Splitting the Hedgehog signal: Sex and Patterning in Drosophila. Development, 132, 4801-4810.
Horabin, J. I., Walthall, S., Vied, C., & Moses, M. (2003). A Positive role for Patched in Hedgehog signaling revealed by the intracellular trafficking of Sex-lethal, the Drosophila Sex Determination Master Switch. Development, 130, 6101-6109.
Vied. C., Halachmi, N., Salzberg, A., & Horabin, J. I. (2003). . Antizyme is a Target of Sex-lethal in the Drosophila Germline and appears to act downstream of Hedgehog to regulate Sex-lethal and Cyclin B. Developmental Biology, 253, 214-229.
Vied, C., & Horabin, J. I. (2001). A new target for Hedgehog: the sex determination masterswitch, Sex-lethal, responds to Hedgehog signaling in the Drosophila germline. Development, 128, 2649-2660.
Waterbury, J., Horabin, J. I., Bopp, D., & Schedl, P. (2000). Sex determination in the Drosphila germline is dictated by the sexual identity of the surrounding soma. Genetics, 155, 1741-1756.
Bopp, D., Calhoun, G., Horabin, J. I., Samuels, M. E., & Schedl, P. (1996). Sex specific control of Sex-lethal is a common mechanism for sex determination in the Genus Drosophila. Development, 122, 971-982.
Horabin, J. I., & Schedl, P. (1996). Splicing of the Drosophila Sex-lethal early transcripts involves exon skipping that is independent of Sex-lethal protein. RNA, 2, 1-10.
Horabin, J. I., Bopp, D., Waterbury, J., & Schedl, P. (1995). Selection and Maintenance of Sexual Identity in the Drosophila germline. Genetics, 141, 1521-1535.
Lantz, V., Chang, J., Horabin, J. I., Bopp, D., & Schedl, P. (1994). The Drosophila orb RNA-Binding Protein is required for the formation of the Egg Chamber and establishment of Polarity. Genes & Development, 8, 598-613.
Horabin, J. I., & Schedl, P. (1993). Sex-lethal autoregulation requires multiple cis-acting elements upstream and downstream of the male exon and appears to pivot primarily on the male exon 5' splice site. Mol. Cell Biol, 13, 7734-7746.
Bopp, D., Horabin, J. I., Lersch, R. A., Cline, T. W., & Schedl, P. (1993). . Expression of the Sex-lethal gene is controlled at multiple levels during Drosophila Oogenesis. Development, 118, 797-812.
Horabin, J. I., & Schedl, P. (1993). Regulated splicing of the Drosophila Sex-lethal male exon involves a blockage mechanism. Mol. Cell Biol, 13, 1408-1414.
Bell, L. R., Horabin, J. I., Schedl, P., & Cline, T. W. (1991). Positive Autoregulation of Sex-lethal by Alternative Splicing Maintains the Female Determined State in Drosophila. Cell, 65, 229-239.
Horabin, J. I. (Ed.). (2007). Methods in Molecular Biology: Hedgehog Signaling Protocols. Humana Press, Totowa, NJ 07512.