Related Experiment Video
Updated: Jun 25, 2026

Quantitative Immunofluorescence Assay to Measure the Variation in Protein Levels at Centrosomes
Published on: December 20, 2014
Orc1 controls centriole and centrosome copy number in human cells
Adriana S Hemerly1, Supriya G Prasanth, Khalid Siddiqui
1Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor 11724, NY, USA.
Abstract:
Centrosomes, each containing a pair of centrioles, organize microtubules in animal cells, particularly during mitosis. DNA and centrosomes are normally duplicated once before cell division to maintain optimal genome integrity. We report a new role for the Orc1 protein, a subunit of the origin recognition complex (ORC) that is a key component of the DNA replication licensing machinery, in controlling centriole and centrosome copy number in human cells, independent of its role in DNA replication. Cyclin A promotes Orc1 localization to centrosomes where Orc1 prevents Cyclin E-dependent reduplication of both centrioles and centrosomes in a single cell division cycle. The data suggest that Orc1 is a regulator of centriole and centrosome reduplication as well as the initiation of DNA replication.
Related Concept Videos
Centrosome Duplication
To ensure that each daughter cell receives a centrosome after cell division, centrosome duplication...
Centrosome Duplication
To ensure that each daughter cell receives a centrosome after cell division, centrosome duplication...
Centrioles and Centrosomes
Near the end of the prophase, also called late prophase or "prometaphase,"...
Histone Variants at the Centromere
Karyotyping
Chromosome Structure
The centromere is a DNA sequence that links sister chromatids. This is also where kinetochores, protein complexes to which spindle microtubules attach, are constructed after the chromosome is replicated. The kinetochores allow the spindle microtubules to move the chromosomes within the cell during cell division.
Telomeres consist of non-coding repetitive nucleotide...

