The direction of synthesis of an RNA transcript is 5' to 3'.

Here's why:

* RNA polymerase (the enzyme that synthesizes RNA) adds nucleotides to the 3' end of the growing RNA strand.

* This means that the 5' end of the RNA molecule is the first part synthesized, and the 3' end is the last part synthesized.

* This directionality is important because it ensures that the RNA transcript is produced in the correct order and sequence.

Let me know if you would like to know more about RNA synthesis!