Cover photograph (Copyright © 2008, American Society for Microbiology. All Rights Reserved.): Hyperfilamentation in a colony of a hxk2Δ/hxk2Δ Saccharomyces cerevisiae mutant during growth on solid ammonium-limiting medium supplemented with glucose. Pseudohyphae are formed when yeast cells display an elongated cell morphology and a unipolar budding pattern. Genetic analysis revealed a role of both Snf1- and protein kinase A-dependent mechanisms for the regulation of filamentation on various carbon sources. Sucrose was found to be a prime inducer of filamentation, being capable of inducing pseudohyphal growth on otherwise nonpermissive nitrogen-rich medium through activation of the G-protein-coupled receptor Gpr1. (See related article on page 286.)