Related Experiment Video
Updated: Aug 1, 2026
07:44
High-throughput Purification of Affinity-tagged Recombinant Proteins
Published on: August 26, 2012
Function of the bacterial TATAAT -10 element as single-stranded DNA during RNA polymerase isomerization
1Department of Chemistry and Biochemistry and Molecular Biology Institute, University of California, Post Office Box 951569, Los Angeles, CA 90095-1569, USA.
Summary
Bacterial promoter -10 sequences stabilize initial polymerase binding through duplex interactions. Subsequently, single-stranded DNA elements guide RNA polymerase isomerization to its functional form during transcription initiation.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- The bacterial TATAAT -10 region is a critical promoter element, yet its precise function remains incompletely understood.
- Understanding promoter recognition and initiation is fundamental to gene expression regulation.
Purpose of the Study:
- To elucidate the functional roles of the bacterial -10 promoter region in both double-stranded and single-stranded DNA contexts during transcription initiation.
- To investigate the sequence-specific and non-specific contributions of the -10 region to RNA polymerase binding and isomerization.
Main Methods:
- Electrophoretic mobility shift assays (band-shift) were employed to study polymerase-promoter interactions.
- Mutational analysis of the -10 region was performed in both duplex and melted DNA contexts.
Main Results:
- Unexpectedly, band-shift results in melted DNA revealed a significant sequence-nonspecific contribution to polymerase binding.
- Single-stranded nucleotides within the -10 region predominantly direct RNA polymerase isomerization to the heparin-resistant state.
- This isomerization role diminishes when DNA melting extends beyond the -10 region.
Conclusions:
- Bacterial -10 region sequences serve dual roles: stabilizing initial polymerase binding via duplex interactions and promoting enzyme isomerization as single-stranded DNA.
- Positions -12T and -11A are crucial for promoter recognition in the duplex state.
- These findings clarify the mechanism by which the -10 region facilitates transcription initiation.
More Related Videos
Related Concept Videos
02:10Translesion DNA Polymerases
Translesion (TLS) polymerases rescue stalled DNA polymerases at sites of damaged bases by replacing the replicative polymerase and installing a nucleotide across the damaged site. Doing so, TLS allows additional time for the cell to repair the damage before resuming regular DNA replication.
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
00:43Bacterial RNA Polymerase
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
02:42Transcription Attenuation in Prokaryotes
Transcriptional attenuation occurs when RNA transcription is prematurely terminated due to the formation of a terminator mRNA hairpin structure. Bacteria use these hairpins to regulate the transcription process and control the synthesis of several amino acids including histidine, lysine, threonine, and phenylalanine. Transcription attenuation takes place in the non-coding regions of mRNA.
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
01:53Bacterial Transcription
RNA polymerase (RNAP) carries out DNA-dependent RNA synthesis in both bacteria and eukaryotes. Bacteria do not have a membrane-bound nucleus. So, transcription and translation occur simultaneously, on the same DNA template.
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
00:43Bacterial RNA Polymerase
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
01:29Coordination of Gene Expression Processes in Bacteria
The DNA replication, transcription, and translation processes are intricately coupled in bacteria, allowing efficient gene expression and rapid protein synthesis. While this physical and functional coordination is advantageous, it introduces challenges that bacteria overcome through specific regulatory mechanisms.Coupling of Replication, Transcription, and TranslationThe coupling of replication, transcription, and translation is a hallmark of bacterial gene expression. As the replisome unwinds...