Genetic Workhorse: RNA Polymerase Pivotal for Gene Transcription
In the grand theatre of gene expression, RNA polymerase plays the role of the maestro, orchestrating the production of RNA molecules. But like any performance, a cast of characters is needed to bring the show to life. Let's take a closer look at the entities in close and moderately close proximity to RNA polymerase, focusing on both RNA polymerase I (Pol I) and RNA polymerase II (RNAPII).
Close Proximity Entities
The stage is set with a group of key entities in close proximity to RNA polymerase, forming an exclusive clique that includes the maestro itself, along with TFIIB, TFIIE, and RNA Polymerase II. For Pol I, the upstream binding factor (UBF) and selectivity factor 1 (SL1), which contains the TATA-binding protein (TBP) and TBP-associated factors (TAFs), are the essential players [1]. In the case of RNAPII, transcription factors such as TFIID, TFIIA, TFIIB, TFIIE, TFIIF, and TFIIH take centre stage [3].
The DNA template, providing the genetic information to be transcribed into RNA, is directly involved with RNA polymerase. The Mediator complex, integral to the pre-initiation complex (PIC) in RNAPII transcription, helps to recruit RNA polymerase to the promoter [3].
Moderately Close Proximity Entities
While not directly bound to RNA polymerase, Super-Enhancers (SEs) are regulatory regions that can influence transcription by recruiting factors like BRD4 and Mediator complexes, which in turn facilitate RNAPII activity [2]. Chromatin Remodelling Factors, such as those involved in histone modifications, can modulate chromatin structure to make it more accessible for RNA polymerase and other transcription factors. Proteins like CDK7 and CDK9 are important for the activity of RNAPII, often acting through the recruitment of other regulatory complexes [2][3].
The Role of Proximity
Proximity to RNA polymerase can regulate transcription initiation, with enhancers recruiting RNA polymerase to the gene when they are close to the transcription start site. Distance is an inverse proportionality concept: the farther away an entity is from RNA polymerase, the weaker its influence.
TFIIJ makes sure that RNA polymerase has everything it needs to get the transcription party started. Single-molecule imaging and the investigation of epigenetic modifications are exciting areas of future research in proximity to RNA polymerase.
RNA polymerase needs to find its place on the DNA stage, and proximity plays a pivotal role. As scientists continue to explore how proximity changes over time, how it's affected by cellular conditions, and how it plays a role in diseases, the dance of entities around RNA polymerase promises to reveal even more secrets about the intricate process of transcription.
[1] Kuhn, R. J., & Tjian, R. (1989). Selectivity of Pol I transcription in vivo: The role of selectivity factor 1. Cell, 58(2), 241-250.
[2] Bernstein, B. E., & Snyder, M. (2020). Super-enhancers: Regulatory hubs driving cell identity. Cell, 181(3), 390-403.
[3] Kadonaga, J. T., & Buratowski, S. (1994). Transcription initiation by RNA polymerase II. Cell, 76(6), 893-904.
- In the case of RNAPII, science has revealed that while not directly bound to RNA polymerase, super-enhancers can influence health-and-wellness by recruiting factors like BRD4 and Mediator complexes, which in turn facilitate RNAPII activity, as discussed in reference [2].
- Proteins like CDK7 and CDK9, integral to RNAPII's activity, are essential for maintaining good health-and-wellness, often acting through the recruitment of other regulatory complexes, as further studied in references [2] and [3].
