Role of 4.5S RNA in Assembly of the Bacterial Signal Recognition Particle with Its Receptor

). Given the presence of allthree types of molecules in the SA library, it islikely that semaphorins play a role in stem celladhesion and homing behavior.Our studies identify numerous individualcandidate regulatory molecules, but they alsopave the way for more global approaches tostem cell biology. In particular, the productionof stem cell microarrays will permit the analysisof fluctuations in the genetic program as afunction of permutations in self-renewal, com-mitment, or other stem cell properties (