Q.35 Match the entries in Group Iwith the entries in Group II.
Group I Group II
P. RNAse P 1. Polyadenylation
Q. RNase H 2. Splicing
R. snRNAs 3. Ribozymes
S. CstF 4. DNA-RNAhybrids
(A) P-3, Q-4, R-2, S-1 (B) P-4, Q-3, R-2, S-1
(C) P-3, Q-2, R-1, S-4 (D) P-2, Q-4, R-1, S-3
RNA Processing Enzyme Matching: RNase P, RNase H, snRNAs, CstF
Correct Answer: (A) P-3, Q-4, R-2, S-1. RNase P functions as a ribozyme for tRNA maturation, RNase H degrades DNA-RNA hybrids, snRNAs catalyze splicing via the spliceosome, and CstF mediates polyadenylation.
RNA Maturation Mechanisms
These factors execute essential post-transcriptional modifications ensuring mRNA stability, tRNA functionality, and intron removal. Ribozymes and RNPs coordinate precise cleavages during eukaryotic gene expression.
Correct Matching Explained
P. RNase P → 3. Ribozymes. Catalytic RNA (H1 in humans) cleaves 5′ leader from pre-tRNA precursors, generating mature 5′ ends; protein subunits enhance substrate recognition.
Q. RNase H → 4. DNA-RNA hybrids. Endonuclease hydrolyzes RNA strand in RNA-DNA duplexes, critical for removing RNA primers during replication and degrading retroviral hybrids.
R. snRNAs → 2. Splicing. U1, U2, U4, U5, U6 form spliceosome core, recognizing 5’/3′ splice sites and catalyzing two transesterification reactions for intron excision.
S. CstF → 1. Polyadenylation. Cleavage stimulation factor binds GU-rich downstream sequence, recruiting CPSF for pre-mRNA 3′ end cleavage and poly(A) polymerase addition.
Option Analysis
Option (B) P-4, Q-3, R-2, S-1 incorrectly assigns RNase P to hybrids (tRNA processor) and RNase H to ribozymes (hybrid-specific).
Option (C) P-3, Q-2, R-1, S-4 mismatches RNase H to splicing (hybridase) and snRNAs to polyadenylation (spliceosome components).
Option (D) P-2, Q-4, R-1, S-3 wrongly pairs RNase P with splicing (tRNA ribozyme), snRNAs with polyadenylation, and CstF with hybrids.
Molecular Biology Applications
These enzymes underpin recombinant RNA technologies—RNase H enables cDNA synthesis, snRNP engineering improves splicing therapeutics, CstF regulates transgene expression, and RNase P inspires ribozyme-based gene silencing.
