RNA polymerase complex

Definition

Target type: cellularcomponent

Any complex that possesses RNA polymerase activity; generally comprises a catalytic subunit and one or more additional subunits. [GOC:mah]

The RNA polymerase complex is a molecular machine responsible for transcribing DNA into RNA. It consists of multiple protein subunits that assemble into a complex structure. The core enzyme of RNA polymerase in bacteria consists of five subunits: α2ββ'ω. In eukaryotes, the core enzyme has a similar structure, but it is more complex, with additional subunits including the general transcription factors (TFII) and the mediator complex.

The cellular component of the RNA polymerase complex can be described as follows:

1. **Nucleus:** RNA polymerase complexes are primarily localized within the nucleus of eukaryotic cells. This is where DNA is housed and where transcription occurs.

2. **Nucleolus:** In eukaryotes, a specialized region within the nucleus called the nucleolus is responsible for ribosome biogenesis. Some RNA polymerase complexes, particularly those involved in ribosomal RNA (rRNA) synthesis, are localized within the nucleolus.

3. **Chromatin:** The DNA in the nucleus is organized into chromatin, a complex of DNA and proteins. RNA polymerase complexes bind to specific regions of chromatin called promoters, which are located upstream of genes. The chromatin structure can influence the accessibility of DNA to RNA polymerase, thereby regulating gene expression.

4. **Transcription factors:** Transcription factors are proteins that bind to DNA and regulate gene expression. They interact with RNA polymerase complexes, influencing their ability to initiate and elongate transcription.

5. **Mediator complex:** The mediator complex is a large protein complex that acts as a bridge between transcription factors and RNA polymerase II. It plays a crucial role in coordinating the recruitment of RNA polymerase II to promoters and regulating the initiation and elongation of transcription.

6. **Nucleoplasm:** The nucleoplasm is the fluid within the nucleus that surrounds the chromatin. RNA polymerase complexes can move freely within the nucleoplasm, searching for target genes and initiating transcription.

7. **Nuclear pores:** Nuclear pores are channels in the nuclear envelope that allow molecules to move between the nucleus and cytoplasm. RNA polymerase complexes can move through nuclear pores to enter the cytoplasm and deliver newly synthesized RNA molecules.

The cellular component of the RNA polymerase complex is highly dynamic, constantly moving and interacting with other molecules to regulate gene expression. The specific composition and location of the complex can vary depending on the specific gene being transcribed and the cellular context.'
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Proteins (1)

Compounds (1)