This is pretty straight forward. I think they touch on viral vectors.
Euro vs USA - semantics.
Genes are DNA (the only exception - retroviruses, which convert to DNA once they unwrap) mRNA is a copy of the gene in RNA form. Proteins are copies of the genes in amino acid form (after translating the code of course)
You paper's title . . . did you read the paper?
I'm a (retired) clinical PhD cell and molecular biologist. I've done genetic engineering and worked on making transgenic pigs (for xenotranplantation - to use their organs as a bridge until a suitable human donor can be found).