Extracellular matrix fibrils are involved in the cell-cell interactions of the social prokaryote, The fibrils are composed of a carbohydrate backbone and a set of five integral fibrillar proteins (IFPs) ranging from 14 to 66 kDa. As part of an attempt to understand the function(s) of the IFPs, a mutant (-1:20) was generated that lacks IFP-1:20, one of the fibril proteins, as shown by Western blot analysis of both whole cells and isolated fibrils. Unlike those of the parent strain, the fibrils of the mutant were removed easily from the cells by shear forces. Development in was aberrant - aggregation and early mound formation were delayed by 6-10 h and mature fruiting bodies never formed. Myxospore production was also greatly reduced. Additionally, fibril-mediated cohesion in was changed. Cohesion resulted in chains of cells rather than the characteristic clumps of cells seen for the parent strain. Isolated fibrils, unlike wild-type fibrils, could not rescue cohesion of non-cohesive, fibril-negative cells, supporting the notion that the fibrils were functionally altered. The mutation also reduced developmental gene expression by three- to fourfold in Ω4521, a transposon insertion mutant expressed early in development. Expression of a later developmental gene fusion was not affected, suggesting that the fibrils may not be required for later developmental gene expression. These data suggest that intact fibrils may function early in development to facilitate close cell proximity for signal exchange.


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error