The underlined part of the sentence is TRUE; functional ribosomes do not exist in the nucleus.
After the nuclear RNA Polymerase transcribes the actin gene into actin mRNA, the actin mRNA has to cross b. the nuclear membranes to find a ribosome.
In eukaryotic cells, mRNA is synthesized in the nucleus and then exported through the nuclear membrane to the cytoplasm, where ribosomes are found and translation occurs.