What describes positive splicing control in gene expression?

Positive splicing control in gene expression refers specifically to the process where splicing is regulated and enhanced by specific factors. The correct answer highlights that regulated splicing occurs through the action of activators. These activators are proteins or small RNA molecules that bind to specific sequences in the pre-mRNA, promoting the inclusion of certain exons and facilitating the correct assembly of the spliceosome, which is the molecular complex responsible for removing introns and joining exons.

This form of regulation ensures that only specific mRNA transcripts are produced, allowing for the generation of different protein isoforms depending on the cellular context or developmental stage. In this way, the consequence of positive splicing control directly impacts the diversity of proteins derived from a single gene, ultimately influencing various biological pathways and responses.

The other options do not accurately represent the concept of positive splicing control. No regulation and splicing implies a lack of control; constant repression suggests a mechanism for silencing rather than enhancing splicing; and unregulated expression of all genes does not pertain to the fine-tuning that positive splicing control achieves in gene expression.