Partitioning of the Matrix Fraction of the Golgi Apparatus During Mitosis in Animal Cells

Abstract

The Golgi apparatus is partitioned during mitosis in animal cells by a process of fragmentation, dispersal, and reassembly in each daughter cell. We fractionated the Golgi apparatus in vivo using the drug brefeldin A or a dominant-negative mutant of the Sar1p protein. After these treatments, Golgi enzymes moved back to the endoplasmic reticulum, leaving behind a matrix of Golgi structural proteins. Under these conditions, cells still entered and exited mitosis normally, and their Golgi matrix partitioned in a manner very similar to that of the complete organelle. Thus, the matrix may be the partitioning unit of the Golgi apparatus and may carry the Golgi enzyme–containing membranes into the daughter cells.