Analysis of Ice Nucleation Gene Products by Site-Directed Mutagens

摘要

The project was intended to elucidate the functions of the various parts of an ice nucleation protein. Researchers introduced specific mutations into an ice nucleation gene from the bacterium Pseudomonas syringae by recombinant DNA techniques (genetic engineering). Researchers examined the effects of the mutations on ice nucleation frequencies over a range of temperatures, and on the processing of the ice nucleation protein within the bacterial cell. Increases in the length of a repetitive region within the protein were found to have little effect on nucleation frequencies. Removal of material from one end of the protein (the N-terminus) abolished nucleation at warmer temperatures but had much less effect at cooler temperatures. Preliminary observations suggest that removal of the C-terminus causes abnormal distribution of the protein within the bacterial cell.