I suppose it would start with:
append base sequence run stop dup
I would guess that a protein could be created that initiated ( append base ) with a set of 3 colors at precise frequencies ( I would guess near RGB ) being the base pairs and control:
[ (0GB,R0B,RG0,RGB),(R00,0G0 ,00B)] [ (0 ,1 ,2 ,3 ),(run,stop,duplicate)] [ (A ,C ,G ,T ),(run,stop,duplicate)]
There would need to be a BIOS ( base DNA code ) that created the light sensitive proteins and the general structure as well as a run stop control and cell power.
By adding start code and then a sequence of proteins that fed back or forward on the sequences, it would be possible to generate any structure and identify which sequences were dominant or viable. Added features might be splicing in or out a specific DNA / RNA sequence as well as matching environment control to action. Once there is the ability to add base pairs in sequence then any possible program could be implemented. I would see it as being no different than any library access in python or "C". The library functions would have to be coded and present as well as having an initiator for their effect. A minimum structure would need to extract energy from the environment by way of the citric acid cycle and then apply that energy in the form of ATP to perform the base pair sequencing as well as providing energy for RNA transcription or other mechanisms like active transport. It becomes a simple matter of providing the appropriate software to operate the biological CPU. Just like a flash chip, it could disable reprogramming or extension at the end of its programming cycle. It would essentially be a field programmable life array. Since the basic structure would incorporate replication, it could replicate to any scale before or after programming.
By placing the substrate on top of a horizontally positioned LCD display, it would be possible to program a million "cells" in sequence to produce a 3 dimensional structure which could incorporate a visual interface that took light as input and produced ATP, which would be a signaling amplification device to the structure that would function as chemical signal amplification much like any analog or digital transistor. This would allow the remote instantiation of presence on distant planets as well as the ability to create function logic and structure in one single method that was completely flexible in form and remotely defined through a communication method.
If implemented properly with 2-way communication, the sending organism could be suspended as the remote operated and the information of experience could be reintegrated in the original organism. In this way it would be teleport at the speed of light and allow action as if physically present as well as integration of the knowledge gained as well as having existant capabilities present at a remote asteroid, vehicle, moon, or planet without immediate existential risk.