Messenger RNA, mRNA
mRNA is a single-stranded nucleic acid that is transcripted in the nucleus, complementarily to one strand of the DNA double helix. It transports the genetic information of the DNA into the cytoplasm and serves as a template for the ribosomes, which then produce a specific protein. Before its translation into a protein, the pre-mRNA has to be spliced in the nucleus. Splicing removes parts of the pre-mRNA, the introns, which don't contain relevant information for protein synthesis.