Difference Between Transcriptional and Posttranscriptional Gene Silencing

Abstract. Two distinct gene-silencing phenomena are observed in plants: transcriptional gene silencing (TGS), which involves decreased RNA synthesis because of promoter methylation, and posttranscriptional gene silencing (PTGS), which involves sequence-specific RNA degradation.

1. What is post-transcriptional gene silencing?
2. Is RNAi post-transcriptional gene silencing?
3. What does it mean to silence or enhance transcription of a gene?
4. What is gene silencing called?
5. What are the three post transcriptional modifications?
6. Why is gene silencing important?
7. What does Ptgs stand for?
8. How does siRNA affect gene expression?
9. What is post transcriptional gene regulation?
10. Is gene silencing permanent?
11. Is gene silencing reversible?
12. How can we prevent gene silencing?

What is post-transcriptional gene silencing?

Post-transcriptional gene silencing (PTGS) is one mechanism that degrades specific messenger RNAs and thereby reduces the expression of a specific gene. PTGS has many names: cosuppression in plants, quelling in fungi and RNA interference in animals, but in all cases, degraded mRNA decreases gene expression.

Is RNAi post-transcriptional gene silencing?

RNA silencing, also known as post-transcriptional gene silencing (PTGS) or RNA interference (RNAi) is a mechanism regulating gene expression in a wide range of eukaryotes. RNA silencing is a mechanism in which small RNAs block gene expression by targeting homologous mRNAs without impacting nuclear DNA.

What does it mean to silence or enhance transcription of a gene?

Gene silencing is the regulation of gene expression in a cell to prevent the expression of a certain gene. Gene silencing can occur during either transcription or translation and is often used in research. ... When genes are silenced, their expression is reduced.

What is gene silencing called?

Gene silencing (also known as RNA interference) is a sequence-specific gene inactivation system that downregulates RNA accumulation at the transcriptional or post-transcriptional levels.

What are the three post transcriptional modifications?

These modifications are 5' capping, 3' polyadenylation, and RNA splicing, which occur in the cell nucleus before the RNA is translated.

Why is gene silencing important?

Both transcriptional and post-transcriptional gene silencing are used to regulate endogenous genes. Mechanisms of gene silencing also protect the organism's genome from transposons and viruses. Gene silencing thus may be part of an ancient immune system protecting from such infectious DNA elements.

What does Ptgs stand for?

PTGS

How does siRNA affect gene expression?

The siRNA-induced post transcriptional gene silencing starts with the assembly of the RNA-induced silencing complex (RISC). The complex silences certain gene expression by cleaving the mRNA molecules coding the target genes. ... This cleavage results in mRNA fragments that are further degraded by cellular exonucleases.

What is post transcriptional gene regulation?

Post-transcriptional regulation is the control of gene expression at the RNA level. It occurs once the RNA polymerase has been attached to the gene's promoter and is synthesizing the nucleotide sequence. ... These controls are critical for the regulation of many genes across human tissues.

Is gene silencing permanent?

While genome editing technologies, such as CRISPR, “permanently” modify a gene, “temporary” silencing of genes at the mRNA level by siRNAs is desirable in many diseases and would have fewer associated off-target effects. ... Unlike small-molecule inhibitors or antibodies, siRNAs can act at the specific gene level (3).

Is gene silencing reversible?

Silencing can be reversed by adding back copper ions to mimic gene complementation.

How can we prevent gene silencing?

Results

1. Suppression of Gene Silencing by Diverse Plant Viruses. ...
2. The Geminivirus-Encoded AC2 Protein Is a Suppressor of Gene Silencing. ...
3. Vein-Specific Suppression of Silencing by the 19-kDa (“19K”) Protein of TBSV. ...
4. Other Examples in Which Suppression of PTGS Occurs Preferentially in or Near the Veins.