Transcription and Translation Mechanism

Question 1

Antisense RNA (Transcription Level)

Answer 1

Forms a double helix with mRNA and blocks transcription
-ex., the ‘Flavr Savr’ tomato- ‘artificial’ gene is transcribed to antisense RNA that greatly reduces translation of a gene involved in ethylene synthesis, delaying ripening

Question 2

RNA interference (Transcription level)

Answer 2

A short stretch of double-strand RNA (~20bp) elicits degradation, by a ribonucleoprotein complex of RNA complementary to either of the RNA strands
-Gene knockout in studies aimed at deducing gene function

Question 3

Attachment of ligands to Shine-Dalgarno sequence in mRNA (Transcription level)

Answer 3

Prevents mRNA (RBS) from binding to the ribosome in E-coli’s, vitamin B1 and B2 bind to mRNA transcripts of genes involved in their biosynthesis (unique) RNA-level feedback inhibitor

Question 4

Regulating translation of splice variants

Answer 4

• Degradation of specific mRNA variants by miRNA and siRNA, may repress the translation of specific splice variants
  -Splicing factor, thus (i.e., RNA-binding proteins) may interact with transcripts of specific exons and introns and splicing machinery to direct maturation of mRNA
• At the transcriptional level, chromatin remodelling may render certain exons inaccessible and affect expressed splice variants.