Related Experiment Video

Updated: Oct 8, 2026

Investigation of Protein Recruitment to DNA Lesions Using 405 Nm Laser Micro-irradiation
12:29

Investigation of Protein Recruitment to DNA Lesions Using 405 Nm Laser Micro-irradiation

Published on: March 20, 2018

On the association of DNA primase activity with the nuclear matrix in HeLa S3 cells

A M Martelli1

  • 1Istituto di Anatomia Umana Normale, Università degli Studi di Trieste, Italy.

Cell Biochemistry and Function
|December 1, 1993
PubMed

Insights

Nuclear matrix-bound DNA primase activity is less than 10% of total cell activity and depends on nuclear isolation methods. This finding impacts understanding DNA primase localization and function in cell biology.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • DNA primase is crucial for DNA replication initiation.
  • Its association with the nuclear matrix is poorly understood.
  • Previous studies suggested significant nuclear matrix-bound primase activity.

Purpose of the Study:

  • To accurately reinvestigate DNA primase activity association with the nuclear matrix.
  • To clarify the percentage of total cellular primase bound to the nuclear matrix.
  • To identify factors influencing primase-nuclear matrix association.

Main Methods:

  • Isolation of nuclear matrix from HeLa S3 cells.
  • Extraction of nuclear matrix-bound proteins using high salt (2 M NaCl) and DNase I.
  • Quantification of DNA primase activity in different cellular fractions.
  • Varied nuclear isolation and incubation conditions (37°C).

Main Results:

  • 25-30% of nuclear primase activity resisted extraction, suggesting matrix association.
  • However, matrix-bound primase represented less than 10% of total cellular activity.
  • High primase association was dependent on a 37°C incubation of isolated nuclei.
  • Nuclear preparation methods significantly impacted recovered primase activity.

Conclusions:

  • The association of DNA primase with the nuclear matrix is lower than previously reported.
  • Nuclear isolation and incubation conditions critically affect observed primase-nuclear matrix binding.
  • Methodological artifacts can significantly influence the interpretation of DNA primase localization studies.

More Related Videos

DNA Sequence Recognition by DNA Primase Using High-Throughput Primase Profiling08:04

DNA Sequence Recognition by DNA Primase Using High-Throughput Primase Profiling

Published on: October 8, 2019

Visualizing Single-Stranded DNA Foci in the G1 Phase of the Cell Cycle08:30

Visualizing Single-Stranded DNA Foci in the G1 Phase of the Cell Cycle

Published on: December 22, 2023

Related Concept Videos

DNA Helicases00:55

DNA Helicases

DNA unwinding helicase enzymes are a type of motor protein. Motor proteins can translocate along filaments or polymers using energy generated from ATP hydrolysis. Helicases are involved in all the important cellular processes where DNA unwinding is required, such as DNA replication, repair, recombination, and transcription. They are present in all living organisms, but vary in their structure, function, and mechanism of action. For example, in prokaryotes, DnaB helicase binds and translocates...
The Replisome03:01

The Replisome

DNA replication is carried out by a large complex of proteins that act in a coordinated matter to achieve high-fidelity DNA replication. Together this complex is known as the DNA replication machinery or the replisome.
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
Homologous Recombination02:31

Homologous Recombination

The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
Restarting Stalled Replication Forks02:37

Restarting Stalled Replication Forks

DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...
S-Cdk Initiates DNA Replication02:38

S-Cdk Initiates DNA Replication

The cell cycle is a series of events leading to DNA duplication followed by the division of cell content to form two daughter cells. The cell cycle progresses in four stages—the cell increases in size (gap 1 or G1-phase), duplicates its DNA (synthesis or S-phase), prepares to divide (gap 2 or G2-phase), and divides (mitosis or M-phase).
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
Single-Strand DNA Binding Proteins01:03

Single-Strand DNA Binding Proteins

For successful DNA replication, the unwinding of double-stranded DNA must be accompanied by stabilization and protection of the separated single strands of the DNA. This crucial task is performed by single-strand DNA-binding (SSB) proteins. They bind to the DNA in a sequence-independent manner, which means that the nitrogenous bases of the DNA need not be present in a specific order for binding of SSB proteins to it. The binding of SSB proteins straightens single-stranded DNA (ssDNA) and makes...