PRIM1
Description
The PRIM1 (DNA primase subunit 1) is a protein-coding gene located on chromosome 12.
PRIM1 encodes DNA primase small subunit, an enzyme crucial for DNA replication in eukaryotic cells. It forms a heterodimer with a large subunit to synthesize small RNA primers needed for Okazaki fragments during discontinuous DNA replication. PRIM1, a 49 kDa protein, is a key component of the DNA polymerase alpha complex, along with the catalytic subunit POLA1 and the regulatory subunits POLA2 and PRIM2.
PRIM1, also known as DNA primase 49 kDa subunit, is the catalytic subunit of the DNA primase complex. It is a component of the DNA polymerase alpha complex (also known as the alpha DNA polymerase-primase complex - primosome/replisome) which plays an essential role in the initiation of DNA synthesis. During the S phase of the cell cycle, the DNA polymerase alpha complex is recruited to DNA at the replicative forks. The primase subunit of the polymerase alpha complex initiates DNA synthesis by oligomerising short RNA primers on both leading and lagging strands. These primers are initially extended by the polymerase alpha catalytic subunit and subsequently transferred to polymerase delta and polymerase epsilon for processive synthesis on the lagging and leading strand, respectively. Both PRIM1 and its regulatory subunit PRIM2 are necessary for the initial di-nucleotide formation, but the extension of the primer depends only on PRIM1. PRIM1 synthesizes 9-mer RNA primers (also known as the 'unit length' RNA primers). It incorporates only ribonucleotides in the presence of ribo- and deoxy-nucleotide triphosphates (rNTPs, dNTPs). PRIM1 requires template thymine or cytidine to start the RNA primer synthesis, with an adenine or guanine at its 5'-end. It binds single stranded DNA.
PRIM1 is also known as PDIL, p49.
