Two transcripts of the same ecdysterone-controlled gene are differentially associated with ribosomes

Area of Science:

• Molecular Biology
• Genetics
• Developmental Biology

Background:

• Ecdysterone is a key hormone regulating insect development.
• Gene I-18C in Chironomus tentans is controlled by ecdysterone.
• Differential splicing generates multiple RNA transcripts from a single gene.

Purpose of the Study:

• To investigate the functional differences between two ecdysterone-controlled I-18C gene transcripts.
• To determine the translational status of each transcript.

Main Methods:

• Differential splicing analysis of gene I-18C.
• Centrifugation of cytoplasmic extracts using sucrose gradients.
• Analysis of RNA-protein complexes using CsCl-buoyant-density gradients.

Main Results:

• Two transcripts (1.8-kb and 4.6-kb) were identified from the I-18C gene.
• The 1.8-kb RNA transcript contains an open reading frame (ORF) of 417 nucleotides.
• The 4.6-kb RNA transcript lacks a significant ORF.
• Velocity sedimentation and buoyant density gradients showed the 1.8-kb RNA is polysome-associated.
• The 4.6-kb RNA was found in free ribonucleic acid-protein complexes and monosomes.

Conclusions:

• Differential splicing of the I-18C gene produces distinct functional RNA molecules.
• The 1.8-kb transcript is translationally active and likely produces a functional protein.
• The 4.6-kb transcript is not actively translated and may have regulatory or structural roles.