Post-transcriptional control – antisense pairing: RNA that is complementary to a segment of another RNA and can base-pair with it to modulate stability or translation is known as what?

Introduction / Context:
Cells often regulate gene expression after transcription by using complementary RNAs that bind target transcripts. This antisense mechanism is exploited in research, medicine, and synthetic biology to silence or fine-tune gene output without altering DNA sequences.

Given Data / Assumptions:

• Complementarity implies Watson–Crick base pairing.
• Binding can block ribosome access, alter splicing, or recruit degradation pathways.
• Terminology distinguishes antisense from other RNA categories (missense/nonsense refer to coding mutations, not regulatory RNAs).

Concept / Approach:
Antisense RNA is defined by its sequence complementarity to a target RNA. In bacteria, small antisense RNAs pair with mRNAs to affect translation or stability. In eukaryotes, synthetic antisense oligonucleotides or endogenous long noncoding antisense transcripts can modulate splicing, nuclear export, or degradation via RNase H or RISC-related pathways when designed accordingly. The key is sequence complementarity that allows base pairing to a specific target region.

Step-by-Step Solution:
Identify that the question describes RNA–RNA binding via complementarity. Map this behavior to “antisense RNA.” Exclude terms for coding sequence mutation types (missense/nonsense). Select the precise regulatory term.

Verification / Alternative check:
Classical plasmid replication control (RNA I/RNA II in ColE1) and modern antisense therapies (e.g., splice-modulating oligos) demonstrate this mechanism.

Why Other Options Are Wrong:
Missense/nonsense describe protein-coding changes in DNA/mRNA; “none” is incorrect; guide RNA serves RNA editing in some systems and is a different concept.

Common Pitfalls:
Confusing antisense RNAs with siRNA/miRNA pathways; while related in outcome, the biogenesis and effector complexes differ.

Final Answer:
Antisense RNA.