AAMC Official guide BB Q clarification

[Foggybrain]

In contrast to the conventional thought that prokaryotic transcription and translation are coupled, scientists have observed the intracellular localization of mRNA in Escherichia coli. The locations of cat and lacY transcripts were determined in living E. coli cells. The gene cat encodes the soluble protein chloramphenicol acetyltransferase, and lacY encodes the membrane-bound lactose permease. Six copies of the binding sequence (6xbs) for the phage MS2 coat protein were inserted upstream of these genes in E. coli cells. The locations of the transcripts were visualized using fluorescence microscopy of cells expressing the MS2 coat protein fused to green fluorescent protein (MS2–GFP). The cat6xbs transcript formed a helix-like structure within the cytoplasm, and the lacY6xbs transcript was localized near the cell membrane.

Can someone please clarify this passage portion for me, in particular the sentence in red color. Does it mean that we are using a bacteria DNA which contains 2 genes (cat and LacY) and we have inserted the virus (baceteriophage) DNA, named MS2 gene, at a location that is to the right of the bacterial genes? Thank you in advance.

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[RocuROMANium]

Yes, the phage (virus) genes were inserted upstream (to the left not right) of the bacterial genes cat and lacY.

 

[Foggybrain]

Yes, the phage (virus) genes were inserted upstream (to the left not right) of the bacterial genes cat and lacY.

Thanks.

Could you please further clarify what does this sentence mean as I am having some trouble understanding it: "Six copies of the binding sequence (6xbs) for the phage MS2 coat protein".

Does it refer to the virus (phage) DNA that binds to/integrates within a bacteria DNA sequence (6xbs)? This viral DNA codes for the viral coat protein called MS2?

 

[RocuROMANium]

The bacterial genes of interest are cat and lacY. The viral or phage gene of interest is binding sequence (bs). The investigators took 6 copies of binding sequence (hence 6xbs) and inserted it upstream of the bacterial genes cat and lacY. They did this so that when the bacteria transcribe the operon containing cat and lacY, the viral DNA 6xbs will be transcribed too. The viral MS2 protein, which is fused to green fluorescent protein, binds to 6xbs mRNA and fluoresces. This reveals the location of the cat and lacY transcripts because they are connected to 6xbs.

 

[Foggybrain]

The bacterial genes of interest are cat and lacY. The viral or phage gene of interest is binding sequence (bs). The investigators took 6 copies of binding sequence (hence 6xbs) and inserted it upstream of the bacterial genes cat and lacY. They did this so that when the bacteria transcribe the operon containing cat and lacY, the viral DNA 6xbs will be transcribed too. The viral MS2 protein, which is fused to green fluorescent protein, binds to 6xbs mRNA and fluoresces. This reveals the location of the cat and lacY transcripts because they are connected to 6xbs.

Thank you so much DT III for the clear explanation.