DNA Replication in Eukaryotes vs

DNA Replication Proteins

• The protein responsible for re-assembling nucleosomes after DNA replication is Chromatin Assembly Factor-1 (CAF-1).
• The protein that prevents chromosome end shortening is Telomerase.
• The protein involved in the proof-reading function during DNA replication is DNA Polymerase.
• The protein responsible for unwinding the DNA double helix during replication is Helicase.
• The protein involved in the formation of RNA primers during DNA replication is Primase.
• The protein responsible for joining the Okazaki fragments during DNA replication is DNA Ligase.
• The protein responsible for relieving the torsional strain ahead of the replication fork is Topoisomerase.
• The protein responsible for adding nucleotides to the growing DNA strand during replication is DNA Polymerase.

DNA Replication in Prokaryotes

• DNA replication in prokaryotes is initiated at a single origin.
• The function of DNA Gyrase in prokaryotic DNA replication is to relieve the torsional strain ahead of the replication fork.
• The size of the origin of replication in prokaryotes is approximately 245 bp.
• Two forks are formed during DNA replication in prokaryotes.
• The function of Dna A and Dna B in prokaryotic DNA replication is to initiate and maintain the replication process.

DNA Replication in Eukaryotes

• DNA replication in eukaryotes is initiated at multiple origins.
• The function of Topoisomerases in eukaryotic DNA replication is to relieve the torsional strain ahead of the replication fork.
• The size of the origin of replication in eukaryotes varies, but is typically around 100-200 bp.
• Multiple forks are formed during DNA replication in eukaryotes.

Telomeres and Telomerase

• Telomeres are repetitive DNA sequences (TTAGGG) that cap the ends of chromosomes, protecting them from degradation.
• The function of Telomerase is to maintain telomere length by adding telomere repeats to the ends of chromosomes.
• Telomerase is a characteristic of telomeres.

Other DNA Replication-Related Facts

• The function of DNA Ligase is to seal the gaps between Okazaki fragments.
• The role of Topoisomerase II in DNA replication is to relieve the torsional strain ahead of the replication fork.
• The function of DNA polymerase beta is to repair DNA damage.
• The minimum number of origins required to replicate the human genome in an 8-hour S phase, assuming replication forks move at 50 nucleotides per second, is approximately 30,000.
• The minimum number of origins required to replicate the human genome if there are no time constraints is approximately 2,500.
• The consequence of adding dideoxycytidine triphosphate (ddCTP) in large excess over the concentration of deoxycytidine triphosphate (dCTP) in a DNA replication reaction is to terminate DNA synthesis.
• The function of single-strand DNA binding protein in DNA replication is to stabilize the single-stranded DNA template.
• Defects in DNA replication and changes in chromatin structure can cause diseases such as Bloom syndrome and Werner syndrome.