Final answer:
Targeted gene knockdown (KD) is a biotechnological approach to reduce gene expression in organisms or specific cells, often using post-transcriptional strategies to target mRNA, resulting in inhibited translation into proteins.
Step-by-step explanation:
Targeted Gene Knockdown (KD)
Targeted gene knockdown (KD) refers to genetic engineering techniques that reduce the expression of specific genes within an organism or cells. This can result in a knockdown organism or target specific knockdown genes with nonheritable changes. The process typically involves post-transcriptional strategies that target mRNA to prevent its translation into proteins. Gene silencing, carried out by technologies such as small interfering RNAs (siRNAs), microRNAs (miRNAs), or peptide nucleic acids (PNAs), can selectively interfere with the translation process. Moreover, targeted gene knockdown can be facilitated by CRISPR interference (CRISPRi), where a modified CRISPR/Cas9 complex without endonuclease activity simply blocks transcription. This approach is valuable for researching gene functions and is also considered for therapeutic applications.