Explain the ramifications to the process of transcription if the following occurs:
A) The termination sequence of a gene is removed
In the process of transcription, the termination sequence is a critical component for ending the transcription of a gene. The removal of the termination sequence can have significant ramifications on the transcription process and the resulting gene expression.
When a gene is transcribed, it starts with the binding of RNA polymerase enzyme to the promoter region of the gene. As RNA polymerase moves along the DNA template strand, it synthesizes an RNA molecule by adding complementary nucleotides. Eventually, it reaches the termination sequence, which signals the end of transcription.
If the termination sequence is removed, several consequences can occur:
1. Prolonged transcription: Without a termination sequence, the RNA polymerase will continue synthesizing RNA beyond the intended length of the gene. It may continue transcribing neighboring genes or even non-coding regions of the DNA. This can lead to the production of extended RNA transcripts that could encode non-functional or abnormal proteins.
2. Collisions with other genes: In instances where neighboring genes exist in close proximity on the DNA strand, the absence of a termination sequence can cause collisions between RNA polymerase molecules transcribing different genes. Such collisions can disrupt both transcription processes, leading to errors in RNA production and possibly affecting the synthesis of multiple proteins.
3. Readthrough transcription: In some cases, without a proper termination sequence, RNA polymerase may undergo readthrough transcription. This means that it can continue transcribing into the downstream regulatory regions or even into the next gene. This can interfere with the regulation of gene expression, potentially affecting the activity or function of the downstream genes.
4. Altered mRNA processing: The presence of a termination sequence is also necessary for proper mRNA processing, including the addition of a poly(A) tail and the removal of introns through splicing. Without the termination sequence, mRNA processing may be compromised, and the resulting mRNA molecules may lack important regulatory elements or contain unprocessed introns, rendering them non-functional or unstable.
Overall, the removal of the termination sequence can disrupt the normal transcription process, leading to errors in gene expression and potentially impacting the functionality of the resulting RNA molecules and proteins.