International Review of Cytology presents current advances and comprehensive reviews in cell biology - both plant and animal. Authored by some of the foremost scientists in the field, each volume provides up-to-date information and directions for future research. Articles in this volume address biosynthesis and alternate targeting of the lysosomal cysteine protesase cathepsin L; microtubule-associated proteins and their essential roles during mitosis; molecular and functional analysis of the dictyostelium centrosome; polytene chromosomes; and insect basic leucine zipper proteins and their role in cyclic AMP dependent regulation of gene expression.