Coactosin-like protein 1 (Cotl1), a member of the actin-depolymerizing factor (ADF)/cofilin family, was first purified from a soluble fraction of Dictyostelium discoideum cells. Neuronal migration requires cytoskeletal remodeling and actin regulation. Although Cotl1 strongly binds to F-actin, the role of Cotl1 in neuronal migration remains undescribed. In this study, we revealed that Cotl1 overexpression impaired migration of both early- and late-born neurons during mouse corticogenesis. Moreover, Cotl1 overexpression delayed, rather than blocked, neuronal migration in late-born neurons. Cotl1 expression disturbed the morphology of migrating neurons, lengthening the leading processes. This study is the first to investigate the function of Cotl1, and the results indicate that Cotl1 is involved in the regulation of neuronal migration and morphogenesis.
Actins ; Animals ; Dictyostelium ; Humans ; Mice ; Morphogenesis ; Neurons

The investigation of the mechanism of biological pattern has been an important topic of life sciences, especially, of developmental biology, for a long time. It is an interdisciplinary problem and many researching data have been obtained and some theories have been structured from many points of view in science. However, up to now, the actual mechanism is still a fascinating puzzle and needs more studies. In this paper, we try to construct a cellular automata model of biological pattern. This model defines the individual model cells and their behaviors, cell-cell interactions, and cell-environment interactions. As an application, we present a new discrete model to simulate the aggregation phase of the development of Dictyostelium discoideum with the concept of "inducing switch".
Animals ; Cell Aggregation ; physiology ; Cell Movement ; physiology ; Dictyostelium ; cytology ; physiology ; Models, Biological

The investigation of the mechanism of biological pattern has been an important topic of life sciences, especially of developmental biology, for a long time. We have established a cellular automata model of biological pattern formation, which defines how to form a biological pattern from individual cells and their behaviors, cell-cell interactions, and cell-environment interactions. In this paper, we use that model to simulate the growth pattern of the bacterial colonies in consideration of the effects of both nutrient and metabolite on the cell's reproduction.
Animals ; Bacteria ; growth & development ; Bacterial Adhesion ; Colony Count, Microbial ; Computer Simulation ; Dictyostelium ; growth & development ; Humans ; Models, Biological

An expression system is described for high-yield production of recombinant soluble human FasL (shFasL) in Dictyostelium discoideum cells. DNA encoding amino acids 141 - 281 of hFasL was PCR amplified from cDNA derived from activated human neutrophils. The resulting product was fused with a DNA fragment encoding hCG-beta signal peptide and cloned in the expression vector pMB12neo. Dictyostelium strain AX3 was transfected with this plasmid, yielding a recombinant strain called AX3-pCESFL95-H3. In order to improve the shFasL expression level, pMB12neo was optimized by replacing its transcriptional terminator/ polyadenylation segment of the 2H3 gene with an actin8 terminator/polyadenylation segment, yielding derived expression vector pMB74. The recombinant Dictyostelium strain called AX3-pLu8 was generated with this new plasmid. When the recombinant cells were cultivated in a complex HL-5C medium, a cell density of (1.5 - 2) x 10(7)/mL was reached, and the shFasL level expressed by strains AX3-pCESFL95-H3 and AX3-pLu8 was 23.5 microg/L and 206 microg/L, respectively. By using a newly developed synthetic medium called SIH as culture medium, higher cell density of (4 - 5) x 10(7)/mL was achieved. Correspondently, 111 microg/L and 420 microg/L shFasL were secreted by recombinant strains AX3-pCESFL95-H3 and AX3-pLu8, respectively.
Animals ; Chorionic Gonadotropin, beta Subunit, Human ; genetics ; Culture Media ; Dictyostelium ; genetics ; growth & development ; metabolism ; Fas Ligand Protein ; biosynthesis ; genetics ; Humans ; Neutrophils ; metabolism ; Recombinant Proteins ; biosynthesis ; genetics

Little is known about pre-mRNA splicing in Dictyostelium discoideum although its genome has been completely sequenced. Our analysis suggests that pre-mRNA splicing plays an important role in D. discoideum gene expression as two thirds of its genes contain at least one intron. Ongoing curation of the genome to date has revealed 40 genes in D. discoideum with clear evidence of alternative splicing, supporting the existence of alternative splicing in this unicellular organism. We identified 160 candidate U2-type spliceosomal proteins and related factors in D. discoideum based on 264 known human genes involved in splicing. Spliceosomal small ribonucleoproteins (snRNPs), PRP19 complex proteins and late-acting proteins are highly conserved in D. discoideum and throughout the metazoa. In non-snRNP and hnRNP families, D. discoideum orthologs are closer to those in A. thaliana, D. melanogaster and H. sapiens than to their counterparts in S. cerevisiae. Several splicing regulators, including SR proteins and CUG-binding proteins, were found in D. discoideum, but not in yeast. Our comprehensive catalog of spliceosomal proteins provides useful information for future studies of splicing in D. discoideum where the efficient genetic and biochemical manipulation will also further our general understanding of pre-mRNA splicing.
Alternative Splicing ; Animals ; Arabidopsis ; genetics ; Dictyostelium ; genetics ; Drosophila melanogaster ; genetics ; Genome, Protozoan ; Humans ; Phylogeny ; Ribonucleoproteins, Small Nuclear ; classification ; genetics ; Saccharomyces cerevisiae ; genetics ; Spliceosomes ; genetics ; metabolism

Animals ; Chemotaxis ; physiology ; Dictyostelium ; genetics ; metabolism ; physiology ; Genes, Protozoan ; genetics ; physiology ; Genes, ras ; genetics ; physiology ; Phosphatidylinositol 3-Kinase ; genetics ; metabolism ; Protein-Serine-Threonine Kinases ; genetics ; metabolism ; Proto-Oncogene Proteins ; genetics ; metabolism ; Protozoan Proteins ; genetics ; metabolism ; Signal Transduction ; Transcription Factors ; genetics ; metabolism