The slime mold Dictyostelium discoideum provides an exceptional experimental system for investigating thr regulation of developmental timing due to several unique timing features including: 1) the capacity to identify and characterize the individual rate-limiting components f developmental timers which cue the consecutive stages of morphogenesis; 2) the capacity to isolate a unique class of timer mutants in which individual rate-limiting components are either contracted, expanded, or in one case eliminated, without affecting the sequence of morphogenetic stages; 3) the capacity to stimulate by disaggregation the rapid recapitulation of morphogenesis, which then reoccurs in one-tenth the original time; 4) the capacity to stimulate a reverse program of """"""""erasure"""""""" and dedifferentiation by simply disaggregating developing cells and resuspending them in nutrient medium, and 5) the capacity to stimulate parallel programs of dedifferentiation and redifferentiation in the same cell. We will continue to exploit these unique timing features in order to investigate the regulation of developmental timing and gene expression during the forward program of morphogenesis and the reverse program of erasure and didifferentiation. We propose to 1) investigate the relationship between the rate-limiting components of the preaggregative period and the regulation of associated gene expression, 2) isolate and characterize new timer mutants, 3) examine the newly discovered phenomenon of high frequency """"""""switching"""""""" in timer mutants, 4) test whether transposable genetic elements are involved in """"""""switching"""""""", 5) investigate the mechanisms involved in turning vegetative genes on and developmental genes off during the erasure process, and 6) continue to isolate and characterize new erasure-defective, or dedifferentiation-defective mutants. In the studies involving gene regulation, the programs of protein synthesis will be assessed by high resolution 2D-PAGE, and charges in the levels of specific mRNA's will be assessed by northern blots employing cloned DNA's containing developmentally regulated genes. Our ultimate goals are 1) to understand why morphogenetic events happen when they do andy why genes are turned on and off at exact times in a developmental program, 2) to test whether mobile genetic elements are involved in the regulation of developmental timing, and 3) to elucidate the mechanism of the """"""""erasure event"""""""" which initiates the program of dedifferentiation.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM025832-12
Application #
3273341
Study Section
Molecular Cytology Study Section (CTY)
Project Start
1979-09-01
Project End
1992-08-31
Budget Start
1990-09-01
Budget End
1992-08-31
Support Year
12
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Iowa
Department
Type
Schools of Arts and Sciences
DUNS #
041294109
City
Iowa City
State
IA
Country
United States
Zip Code
52242
Chandrasekhar, A; Ennis, H L; Soll, D R (1992) Biological and molecular correlates between induced dedifferentiation and spore germination in Dictyostelium. Development 116:417-25
Fukui, Y; Murray, J; Riddelle, K S et al. (1991) Cell behavior and actomyosin organization in Dictyostelium during substrate exploration. Cell Struct Funct 16:289-301
Chandrasekhar, A; Rotman, M; Kraft, B et al. (1990) Developmental mechanisms regulating the rapid decrease in a cohesion glycoprotein mRNA in Dictyostelium function primarily at the level of mRNA degradation. Dev Biol 141:262-9
Soll, D R; Wessels, D; Murray, J et al. (1990) Intracellular vesicle movement, cAMP and myosin II in Dictyostelium. Dev Genet 11:341-53
Wessels, D; Schroeder, N A; Voss, E et al. (1989) cAMP-mediated inhibition of intracellular particle movement and actin reorganization in Dictyostelium. J Cell Biol 109:2841-51
Kraft, B; Chandrasekhar, A; Rotman, M et al. (1989) Dictyostelium erasure mutant HI4 abnormally retains development-specific mRNAs during dedifferentiation. Dev Biol 136:363-71
Soll, D R (1988) High-frequency switching in Candida albicans and its relations to vaginal candidiasis. Am J Obstet Gynecol 158:997-1001
Soll, D R (1988) ""DMS,"" a computer-assisted system for quantitating motility, the dynamics of cytoplasmic flow, and pseudopod formation: its application to Dictyostelium chemotaxis. Cell Motil Cytoskeleton 10:91-106
Wessels, D; Soll, D R; Knecht, D et al. (1988) Cell motility and chemotaxis in Dictyostelium amebae lacking myosin heavy chain. Dev Biol 128:164-77
Soll, D R; Voss, E; Varnum-Finney, B et al. (1988) ""Dynamic Morphology System"": a method for quantitating changes in shape, pseudopod formation, and motion in normal and mutant amoebae of Dictyostelium discoideum. J Cell Biochem 37:177-92

Showing the most recent 10 out of 27 publications