How are introns removed from the mRNA transcript?

introns removed from the mRNA transcript by RNA splicing.

Explanation:

The noncoding region is called as introns and these noncoding regions are removed by a process called splicing.

Introns are removed from the mRNA transcript because these are noncoding regions.

Splicing removes the introns and they join the coding region (exons).

Splicing occurs inside the nucleus after transcription or during the transcription process and this process form a mature mRNA and then it is translated to generate protein.

Thus introns removed from the mRNA transcript by RNA splicing to form a mature mRNA.