Final answer:
The rho-dependent transcription termination in prokaryotes involves the rho protein causing RNA polymerase to stall at a run of G nucleotides, which allows dissociation of the mRNA from the DNA template.
Step-by-step explanation:
The rho-dependent mechanism of transcription termination requires the rho protein, an ATP-dependent helicase that interacts with RNA polymerase. As RNA polymerase nears the end of a gene, it encounters a sequence of G nucleotides on the DNA template, which causes it to stall.
The rho protein, tracking along the mRNA, then collides with the stalled polymerase, leading to the breakage of hydrogen bonds between the nascent RNA and the DNA template and ultimately releasing the newly synthesized mRNA.