In mammalian cells, the primary mRNA transcript transcribed from the CALC CALC\,CALC gene can be processed in two distinct ways. In thyroid cells, exons 1–4 are joined to produce the mature mRNA for calcitonin. In neural cells, exon 4 is skipped, and exons 1–3 are joined directly to exons 5 and 6 to produce the mature mRNA for calcitonin gene-related peptide (CGRP).
At which level of control is gene expression being regulated in this pathway?
Transcriptional
Post-transcriptional
Translational
Post-translational