Difference Between Centromere and Kinetochore

Centromere and Kinetochore are the two primary structures located in the approximate middle of chromosomes. At the time of cell division, they are extremely important for sister chromatid segregation. The primary difference between Centromere and Kinetochore is that the centromere is the region of the chromosome that holds two sister chromatids, whereas the kinetochore is the disc-shaped protein complex of the chromosome.

Difference Between Centromere and Kinetochore

The below table highlights the primary differences between Centromere and Kinetochore:

Features	Centromere	Kinetochore
Composition	A chromosomal DNA segment that is constrained.	A protein complex that is put together on the centromere of chromosomes.
Observation	Visible with a light microscope.	Visible with an electron microscope.
Structure	Comprised of centric heterochromatin.	Comprised of specialized histone types like CENP-A.
Position	Consists of four positions: telocentric, acrocentric, submetacentric, and metacentric.	Consists of two layers, the inner and outer kinetochores.
Number	It may be holocentric or monocentric.	There is one kinetochore complex per centromere.
Binding with Microtubules	Avoids interacting with microtubules.	About 20 anchoring spots can be found on the outer kinetochore.
Primary Function	Holding sister chromatids together.	Creating a location for the attachment of microtubules.
Corona	Doesn’t possess a corona.	Usually have a corona.
Layers	Have no layers.	Usually has two layers.

What is Centromere?

The centromere is the region of a duplicated chromosome that connects the two sister chromatids. The kind of heterochromatin located in the centromere of a chromosome is known as centric heterochromatin. Pericentric heterochromatin surrounds the centric heterochromatin in both directions. The two sister chromatids that collectively make the replicated chromosome are connected by cohesin protein complexes.

The kinetochore, a protein complex assembled on the centromere of the chromosome, is responsible for binding microtubules to the centromere of the chromosome. On chromosomes, there are two different kinds of centromeres: point centromeres and regional centrosomes. To generate centromeres, point centromeres interact with particular proteins. Regional centromeres can also arise on other DNA sequences; however, the centromere prefers to form on a distinct DNA sequence.

What is Kinetochore?

In the anaphase of cell division, chromosomal centromeres develop a protein complex called a kinetochore, to which spindle microtubules are attached and which pull sister chromatids or chromosomes apart. In contrast to monocentric creatures, which have a single place where kinetochores assemble, holocentric animals show kinetochores assembled across the entire chromosome. Kinetochores help spindle microtubules connect to the chromosome and hold two sister chromatids together along with cohesin protein complexes.

Structure of Kinetochore

The inner and outer kinetochore are the two distinct areas of a kinetochore. The two sister chromatids are kept together by the inner kinetochore’s close association with the centromere region. It contains nucleosomes that lack histone H3 and instead are composed of specialized histones called CENP-A. The spindle microtubules and the outer kinetochore engage in interaction. Following the breakdown of the nuclear envelope, it is assembled on the surface of the chromosome. There are roughly 20 locations for kinetochore microtubule anchoring in the outer kinetochore.

Core Difference between Centromere and Kinetochore

The following are some major differences between Centromere and Kinetochore:

• A kinetochore is a protein complex that binds to the centromere, which is the primary region of condensed chromosomes.
• Under a light microscope, the centromere is clearly visible, whereas an electron microscope makes the kinetochore visible.
• Kinetochore is one kinetochore complex, whereas centromere can be either monocentric or holocentric.
• Centromere is made up of centric heterochromatin, whereas the kinetochore is constructed from certain histone subtypes.

FAQs on Centromere and Kinetochore

1. What is the difference between centrosome centromere and kinetochore?

Answer:

Primary difference between kinetochore and centromere is that a centromere is a chromosomal region that is constrained and contains repeated DNA sequences with a high degree of specialization. While the kinetochore is a protein complex in the shape of a disc that is located in the centromere region of the chromosome.

2. What is the function of the centromere and kinetochore?

Answer:

The kinetochore, a protein complex necessary for effective chromosomal segregation during mitosis, is assembled at the centromere, which serves as the building block for this process.

3. How many centromeres are there in a chromosome?

Answer:

There is only one centromere per chromosome. Microtubules connect to centromeres and drag the chromosomes to the opposing ends of the cell during cell division.

4. What is the structure of centromere?

Answer:

Centromeres can be separated into centromere core and pericentromeric sections, where the pericentromere is in control of sister chromatid cohesion while the core regions serve as the kinetochore’s attachment point.

5. Where is the centromere located?

Answer:

While centromeres are often found at the center of a chromosome, they can also be found close to the middle or in a variety of other locations. In prophase of mitosis, chromosomes are attached to spindle fibers via specialized zones on centromeres known as kinetochores.