Our research is focused on discovering and characterizing
the mechanisms of transcriptional repressors in eukaryotes, and understanding
how their action is integrated into developmental circuits in Drosophila
melanogaster [1-4]. The Drosophila
blastoderm embryo provides one of the premier settings for analysis of
eukaryotic transcriptional regulation, providing a convenient matrix for dissection
of regulatory elements and proteins in physiologically relevant settings. Through creation and analysis of transgenic lines,
we have identified key mechanistic features of transcriptional switches and
regulatory proteins. This work has provided
novel insights into the design of eukaryotic transcriptional enhancers that
indicate many developmental control elements are flexible, loosely structured
``billboard" enhancers that are evolutionarily plastic. Our research has revealed that specific
cis-regulatory rules, or ``grammar" constrains the design of these
billboard enhancers, and specifies the workings of short-range transcriptional
repressors such as Giant, Knirps and Krüppel [5-7]. The identification of quantitative parameters that describe this
transcriptional grammar are being used to model the output of defined
transcriptional elements, using a determinative approach in conjunction with
Dr. Chichia Chiu in Mathematics. This
research is aimed at creating workable bioinformatics tools that will assist in
prediction of quantitative output of candidate regulatory regions in genomic DNA. We have integrated undergraduate researchers
in a variety of aspects of our experimental work, notably in creation of novel genetic
switches and transgenic Drosophila lines.
Under the auspices of this NSF proposal, we will extend their training understanding
the creation and validation of biological models that describe transcriptional
circuits.
[1] Hewitt, G.F., Strunk, B.S., Priputin, T., Wang, X.-D., Amey, R., Pabst, B.A., Kosman, D., Reinitz, J., and Arnosti, D.N. (1999) Transcriptional repression by the Drosophila Giant protein: cis element positioning provides an alternative means of interpreting an effector gradient. Development, 126, 1201-1210.
[2] Keller, S.A., Mao, Y.M., Struffi, P., Margulies, C, Yurk, C.E., Anderson, A.R., Amey, R. L.,Moore, S…and D. N. Arnosti} (2000) dCtBP dependent and independent repression activities of the Drosophila Knirps protein. Mol. Cell. Biol., 20, 7247-7258.
[3] Bethany Strunk, Paolo Struffi, Kevin Wright, Brandon Pabst, Jelani Thomas, Ling Qin, and David N. Arnosti (2001) Role of CtBP in transcriptional repression by the Drosophila giant protein. Developmental Biology, 239, 229-240.
[4] Paolo Struffi, Maria Corado, Meghana M. Kulkarni, and David N. Arnosti (2004) Quantitative contributions of CtBP-dependent and -independent repression activities of Knirps. Development, 131, 2419-2429.
[5] Meghana M. Kulkarni and David N. Arnosti (2003) Information Display by Transcriptional Enhancers. Development, 130, 6569-6575.
[6] David N. Arnosti and Meghana M. Kulkarni (2005) Transcriptional enhancers: intelligent enhanceosomes or flexible billboards? J. Cell. Biochem., 94, 890-898.
[7] Meghana M. Kulkarni and David N. Arnosti} (2005) Cis-regulatory logic of short-range repression in Drosophila. Mol. Cell. Biol. in press.
Lab
Home Page: www.bch.msu.edu/faculty/arnosti.htm