RESEARCH INTERESTS:
Functional genomics: We have used microarrays to discover gene function in development (Van Driessche et al., 2002), de-differentiation (Katoh et al., 2004), spore germination (Xu et al., 2004), drug resistance (Van Driessche et al., 2007) and in chemotaxis (Booth et al., 2005; Mendoza et al., 2007). We also showed that the microarray is a good phenotyping tool for discovering epistatic relationships between six genes in the cAMP-dependent Protein Kinase regulatory pathway (Van Driessche et al., 2005). In collaboration with Dr.
Adam Kuspa, we are generating insertional mutations in most Dictyostelium genes. We are using the mutants to discover gene function by parallel phenotyping and by expression analysis. We are currently focusing on the function of ABC transporter proteins in Dictyostelium development.

The evolution of social behavior in Dictyostelium: Social organisms must deal with cheaters­individuals that reap the benefits of sociality without paying the costs. In Dictyostelium, some cells sacrifice themselves to benefit other cells that may be genetically different, providing a fertile ground for cheating. In collaboration with Drs. Strassmann and Queller at Rice University and with Dr. Adam Kuspa at BCM, we found over 100 genes that participate in social interactions (Santorelli et al., 2008). We are using genetic tools to find and characterize additional genes that determine social decisions, find whether they are involved in rapid-evolutionary arms races, and test how cooperators resist cheating (Foster et al., 2004; Khare and Shaulsky, 2006).

Data Mining: We are collaborating with Dr. Blaz Zupan and his group at the University of Ljubljana in Slovenia to develop new concepts in genetic analysis. Together we have developed a tool that performs automated epistasis analysis http://www.genepath.org/. We also developed a tool that analyzes regulatory sequences in eukaryotic promoters http://www.dictybase.org/. We are currently developing DictyExpress, a web tool that would access and analyze all of our microarray data.

bZIPs and the regulation of gene expression: A central signaling molecule in Dictyostelium is the Differentiation Inducing Factor (DIF-1) – A chlorinated alkylphenone. The mechanism of DIF signal reception is unknown. We isolated several strains that are insensitive to DIF-1 and identified dimA, which encodes a bZIP transcription factor (Thompson et al., 2004). We found another bZIP, dimB, that has overlapping functions with dimA (Huang et al., 2006). We are now mutating the remaining 17 bZIPs in the Dictyostelium genome to investigate their functions.

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SELECTED PUBLICATIONS:

1. Santorelli LA, Thompson CRL, Villegas E, Svetz J, Dinh C, Parikh A, Sucgang R, Kuspa A, Strassmann JE, Queller DC, Shaulsky G (2008). Facultative cheater mutants reveal the genetic complexity of cooperation in social amoebae. Nature 451: 1107-1110.

2. Van Driessche N, Alexander H, Min J, Kuspa A, Alexander S, Shaulsky G (2007). Global Transcriptional Responses to Cisplatin in Dictyostelium discoideum Identify Potential Drug Targets. Proc. Natl. Acad. Sci. USA 104: 15406–15411.

3. Khare A, Shaulsky G (2006). First Among Equals: competition between genetically identical cells. Nat. Rev. Genet. 7: 577-583.

4. Huang E, Blagg SL, Keller T, Katoh M, Shaulsky G, Thompson CR (2006). bZIP Transcription Factor Interactions Regulate DIF Responses in Dictyostelium. Development 133: 449-458.

5. Booth EO, Van Driessche N, Zhuchenko O, Kuspa A, Shaulsky G (2005). Microarray Phenotyping in Dictyostelium Reveals a Regulon of Chemotaxis Genes. Bioinformatics 21: 4371-4377.

6. Van Driessche N, Demsar J, Booth EO, Hill P, Juvan P, Zupan B, Kuspa A, Shaulsky G (2005). Epistasis analysis with global transcriptional phenotypes. Nat. Genet. 37: 471-477.

7. Juvan P, Demsar J, Shaulsky G, Zupan B (2005). GenePath: From Mutations to Genetic Networks and Back. Nucl. Acids Res. 33: W749 - W752. (Web Server issue)

8. Eichinger L, Pachebat JA, Glockner G, Rajandream MA, Sucgang R, Berriman M, Song J, Olsen R, Szafranski K, Xu Q, Tunggal B, Kummerfeld S, Madera M, Konfortov BA, Rivero F, Bankier AT, Lehmann R, Hamlin N, Davies R, Gaudet P, Fey P, Pilcher K, Chen G, Saunders D, Sodergren E, Davis P, Kerhornou A, Nie X, Hall N, Anjard C, Hemphill L, Bason N, Farbrother P, Desany B, Just E, Morio T, Rost R, Churcher C, Cooper J, Haydock S, van Driessche N, Cronin A, Goodhead I, Muzny D, Mourier T, Pain A, Lu M, Harper D, Lindsay R, Hauser H, James K, Quiles M, Madan Babu M, Saito T, Buchrieser C, Wardroper A, Felder M, Thangavelu M, Johnson D, Knights A, Loulseged H, Mungall K, Oliver K, Price C, Quail MA, Urushihara H, Hernandez J, Rabbinowitsch E, Steffen D, Sanders M, Ma J, Kohara Y, Sharp S, Simmonds M, Spiegler S, Tivey A, Sugano S, White B, Walker D, Woodward J, Winckler T, Tanaka Y, Shaulsky G, Schleicher M, Weinstock G, Rosenthal A, Cox EC, Chisholm RL, Gibbs R, Loomis WF, Platzer M, Kay RR, Williams J, Dear PH, Noegel AA, Barrell B, Kuspa A (2005). The genome of the social amoeba Dictyostelium discoideum. Nature 435: 43-57.

9. Foster K, Shaulsky G, Strassmann J, Queller D, Thompson C (2004). Multiple effects of a single gene promote cooperation. Nature 431: 693-696.

For more publications, see listing on Pub Med.

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CONTACT INFORMATION:
Gad Shaulsky, Ph.D.
Department of Molecular and Human Genetics
Baylor College of Medicine
One Baylor Plaza
Houston, Texas 77030, U.S.A.

Telephone: 713-798-8082
Fax: 713-798-1021
E-mail:

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