GROUP LEADER: Maurizio Gatti
SCIENTISTS: Silvia Bonaccorsi, Patrizia Somma, Patrizio Dimitri, Romano Petrucci, Fiammetta Verni'
POSTDOCTORAL FELLOWS: Mark Tudor, Giovanni Cenci, Maria Grazia Giansanti
GRADUATE STUDENTS: Barbara Fasulo
TECHNICAL ASSISTANTS: Giorgio Belloni, Maria Pia Belloni
One of the main interests of our laboratory is the genetic and
molecular analysis of cell division in Drosophila
melanogaster. In the past decade we have developed efficient
methods for the isolation and cytological characterization of
mutations affecting the mitotic cell division of larval
neuroblasts. More recently we have elaborated a series of
techniques that allow detection and analysis of mutations
affecting male meiosis. Primary spermatocyte nuclei are about 25
times larger than neuroblast nuclei and exhibit comparatively
larger spindles. Thus, male meiosis is a particularly suitable
system for the analysis of spindle structure and
immunolocalization of spindle-associated proteins. We are
currently focusing on the genetic and molecular analysis of
meiotic cytokinesis in males. We have already identified 10
mutations that disrupt this process, most of which are caused by
the insertion of a single, marked P element. Moreover, we are
continuing P-mutagenesis to recover new mutants defective in the
completion of cytokinesis. Other mutations affecting cytokinesis
have been isolated by other groups [spaghetti squash (sqh),
diaphanous (dia), peanut (pnut)]. All the genes in hand are
being characterized at several levels: (1) by defining the
primary defects that lead to disruption of cytokinesis in male
meiosis of mutants; (2) by molecular cloning and sequencing of
each gene; (3) by the production of antibodies against the gene
products and their immunolocalization during male meiosis; (4) by
studying functional interactions among genes using a variety of
approaches. Our studies have already led to the identification of
some proteins required for meiotic cytokinesis in males, and to
the definition of their biological roles. We believe that
continuation of this research will provide substantial insight
into the mechanisms underlying cytokinesis in animal cells.
In addition to mutations that disrupt cytokinesis, we are currently analyzing mutations affecting telomere behaviour during both mitosis and male meiosis. We have recently isolated mutations at four loci that cause frequent telomere-telomere attachments. One of the genes specified by these mutations, UbcD1, has been shown to encode an ubiquitin-conjugating enzyme (E2). This suggests that ubiquitin-mediated proteolysis is required for proper telomere behaviour.
Michael L. Goldberg, Section of Genetics and Development, Cornell University, Ithaca, NY
- Gatti M. and Pimpinelli S. (1992) Functional elements in Drosophila melanogaster heterochromatin. Annu. Rev. Genet. 26: 239-275
- Pisano C., Bonaccorsi S. and Gatti M. (1993) The kl-3 loop of the Y chromosome of Drosophila melanogaster binds a tektin-like protein. Genetics, 133: 569-579
- Gatti M., Bonaccorsi S. and Pimpinelli S. (1994) Looking at Drosophila mitotic chromosomes. Methods in Cell Biol. 44, 371-391.
- Cenci G., Bonaccorsi S., Pisano C., Verni' F. and Gatti M. (1994) Chromatin and microtubule organization during premeiotic, meiotic and early postmeiotic stages of Drosophila melanogaster spermatogenesis. J. Cell Sci. 107, 3521-3534
- Gunsalus K., C., Bonaccorsi S., Williams E., Verni' F., Gatti M. and Goldberg M. L. (1995) Mutations in twinstar, a Drosophila gene encoding a cofilin/ADF homolog, result in defects in centrosome migration and cytokinesis. J. Cell Biol., 131, 1243-1259
- Pimpinelli S., Berloco M., Fanti L., Dimitri P., Bonaccorsi S., Marchetti E., Caizzi R., Caggese C. and Gatti M. (1995) Transposable elements are stable structural components of Drosophila melanogaster heterochromatin. Proc. Natl. Acad Sci. USA, 92, 3804-3808.
- Williams B. C., Riedy M. F., Williams E. V., Gatti M. and Goldberg M. L..(1995) The Drosophila kinesin-like protein KLP3A is a midbody component required for central spindle assembly and initiation of cytokinesis. J. Cell Biol., 129, 709-723.
- Giansanti M. G., Bonaccorsi S., Williams B. C., Gunsalus K. C., Goldberg M. L. and Gatti M. (1996) Genes controlling cytokinesis during meiosis in Drosophila males. In: Proceedings on Chromosome segregation and aneuploidy, III. ( A. Abbondandolo, B. K. Vig and Roi R. Eds.) IST Genova, pp 304-316
- Verni' F., Somma M. P., Gandhi R., Goldberg M. L. and Gatti M. (1996) Genes controlling chromosome structure in Drosophila melanogaster. In: Chromosomes Today 12. (N. Henriques-Gil, J. S. Parker and M.J. Puertas Eds.) Chapman and Hall, London, pp 88-103
- Williams B. C., Gatti M. and Goldberg M. L. (1996) Bipolar spindle attachments affect redistribution of ZW10, a Drosophila centromere/kinetochore component required for accurate chromosome segregation. J. Cell Biol., 34, 1127-1140
- Cenci G., Rawson R., Belloni G., Castrillon D. H., Tudor M., Petrucci R., Goldberg M. L., Wasserman S. A. and Gatti M. (1997) UbcD1, a Drosophila ubiquitin conjugating enzyme required for proper telomere behavior. Genes and Dev. 11, 863-875
- Giansanti M. G., Bonaccorsi S., Williams B., Williams E. V., Santolamazza C., Goldberg M. L. and Gatti M. (1997) Mutations in the profilin-encoding gene chickadee reveal interactions between the actin cytoskeleton and the ana-telophase central spindle during meiosis in Drosophila melanogaster males. Genes and Dev., in press
REVIEWS AND SELECTED PAPERS:
- Gatti M., Smith D. A. and Baker B. S. (1983). A gene controlling condensation of heterochromatin in Drosophila melanogaster. Science 221: 83-85.
- Gatti M. and Baker B. S. (1989) Genes controlling essential cell-cycle functions in Drosophila melanogaster. Genes and Development 3: 438-453.
- Gatti M. and Goldberg M. L. (1991) Mutations affecting cell division in Drosophila. Methods in Cell Biol.35: 543-585.