Anti-Termination
It is possible for prokaryotic RNA polymerase to ignore termination signals and continue to transcribe until a downstream termination signal is reached. This mechanism is used by lambda phage. The lambda N gene codes for pN which interacts with polymerase RNA to enable it to read through to genes further downstream. Another antiterminator called pQ also act on RNA polymerase, allowing it to transcribe to downstream genes. This antitermination capability creates an opportunity for the phage to delay the expression of certain gene until they are needed.
Regulation of the Initiation of Translation – micF and ompF
A stress response gene found in Escherichia coli is micF. This gene is able to post-transcriptionally control the expression of a membrane porin gene called ompF (an osmoregulation gene). The micF gene accomplishes this by coding for a short antisense RNA which binds to the ompF mRNA and prevents it from being translated.
Autogenous Control of rRNA Synthesis
A mechanism in the regulation of ribosome expression is the binding of ribosomes to operons responsible for its production. What happens is that if enough of the ribosome is available, a subunit of the ribosome binds to the operon responsible for its production and blocks the polymerase RNA from making more.
Regulation at the Termination of Translation – Tubulin
Tubulin is a structural protein found inside prokaryotic cells. The first part of the tubulin monomer to be translated is the part capable of “finding” and binding to other monomers in the cell. If a the monomer that is still being translated binds with other free monomers in the cell, this sends a signal to the ribosome that no more is needed. Hence, a conformational change in the ribosome causes it to terminate translation.
Reference: Krane, D. 2021. Bio 2110 Molecular Biology Video Lecture. Wright State University – Lake Campus.
