Gas vesicle expression systems, gas vesicle constructs and related genetic circuits, vectors, mammalian cells, hosts, compositions, methods and systems

1. A Gas Vesicle Expression System (GVES) configured for expression, in a mammalian cell, of a gene cluster of gvp genes (GVGC) encoding GV proteins capable of forming a GV type, the Gas Vesicle Expression System comprising:

a GVPA/B gene expression cassette comprising a gvpA or a gvpB gene under control of a mammalian promoter and additional mammalian regulatory regions in a configuration allowing expression of the gvpA or gvpB protein in the mammalian cell; and

one or more additional gvp gene expression cassettes comprising the gvp genes of the GV gene cluster other than the gvpA and gvpB, under control of a mammalian promoter and additional regulatory regions in a configuration allowing expression of the GV proteins other than the gvpA and gvpB in the mammalian cell,

wherein each of the one or more additional gvp gene expression cassette, when comprising two or more gvp genes, further comprises a separation element between the two or more gvp genes configured to provide a separate expression of the corresponding GV protein; and

wherein the GVPA/B gene expression cassette and the one or more additional gvp gene expression cassettes are operably linked by regulatory sequences allowing co-expression of the GV proteins and formation of the GV type in the mammalian cell,

wherein the gas vesicle gene cluster comprises gvp genes from B. megaterium and/or Anabaena flos - aquae ; the gas vesicle gene cluster comprising

gvpB, gvpN, gvpF, gvpG, gvpL, gvpS, gvpK, gvpJ, and gvpU from B. megaterium ; or

gvpA, gvpC, gvpN, gvpJ, gvpK, gvpF, gvpG, gvpV, gvpW from Anabaena flos - aquae ; or

gvpR, gvpN, gvpF, gvpG, gvpL, gvpS, gvpK, gvpJ, gvpT and gvpU from B. megaterium and gvpA gene from Anabaena flos - aquae ; or

gvpA, and gvpC from Anabaena flos - aquae , and gvpN, gvpF, gvpG, gvpL, gvpS, gvpK, gvpJ, and gvpU from B. megaterium ; or

gvpA, gvpC and gvpN from Anabaena flos - aquae , gvpF, gvpG, gvpL, gvpS, gvpK, gvpJ, and gvpU from B. megaterium.

2. The Gas Vesicle Expression System of claim 1 , comprising the GVPA/B gene expression cassette and a single additional gvp gene expression cassette comprising the gvp genes of the GV gene cluster other than the gvpA and gvpB.

3. The Gas Vesicle Expression System of claim 1 , wherein GVPA/B gene expression cassette and one or more additional gvp gene expression cassettes are within a same polynucleotide construct.

4. The Gas Vesicle Expression System of claim 1 , wherein GVPA/B gene expression cassette and one or more additional gvp gene expression cassettes are on at least two separate polynucleotide constructs.

5. The Gas Vesicle Expression System of claim 4 , wherein the one additional gvp gene expression cassette is a single additional gvp gene expression cassette on a Gas Vesicle Polynucleotide Construct (GVPC).

6. The Gas Vesicle Expression system of claim 1 , wherein the gene cluster of gvp genes (GVGC) is a naturally occurring gas vesicle gene cluster, or an engineered gas vesicle gene cluster.

7. The Gas Vesicle Expression system of claim 1 , wherein the gas vesicle gene cluster comprises gvpB, gvpN, gvpF, gvpG, gvpL, gvpS, gvpK, gvpJ, and gvpU from B. megaterium.

8. The Gas Vesicle Expression system of claim 1 , wherein the gas vesicle gene cluster is gvpA, gvpC, gvpN, gvpJ, gvpK, gvpF, gvpG, gvpV, gvpW from Anabaena flos - aquae.

9. The Gas Vesicle Expression system of claim 1 , wherein the gas vesicle gene cluster is a hybrid gas vesicle gene cluster comprising gvpR, gvpN, gvpF, gvpG, gvpL, gvpS, gvpK, gvpJ, gvpT and gvpU from B. megaterium and gvpA gene from Anabaena flos - aquae.

10. The Gas Vesicle Expression system of claim 1 , wherein the gas vesicle gene cluster is a hybrid gas vesicle gene cluster comprising gvpA, and gvpC from Anabaena flos - aquae , and gvpN, gvpF, gvpG, gvpL, gvpS, gvpK, gvpJ, and gvpU from B. megaterium.

11. The Gas Vesicle Expression system of claim 1 , wherein the gas vesicle gene cluster is a hybrid gas vesicle gene cluster comprising gvpA, gvpC and gvpN from Anabaena flos - aquae , gvpF, gvpG, gvpL, gvpS, gvpK, gvpJ, and gvpU from B. megaterium.

12. A composition comprising the Gas Vesicle expression system (GVES) of claim 1 herein together with a suitable vehicle.

13. A genetically engineered mammalian Gas Vesicle Reporting molecular component (GVRMC), the gas vesicle reporting molecular component comprising

the Gas Vesicle expression system (GVES) of claim 1 in which the mammalian regulatory regions comprise a gas vesicle reporting (GVR) target region configured to be activated and/or inhibited by a molecular component of a genetic circuit;

wherein the gvp genes and mammalian regulatory regions are in a configuration allowing expression of the gvp genes through activation and/or inhibition of the gas vesicle reporting (GVR) target region, when the genetic circuit operates according to the circuit design in the mammalian cell.

14. A genetically engineered gas vesicle reporting (GVR) genetic circuit (GVRGC) configured for expression in a mammalian cell in which molecular components are connected one to another in a mammalian cell in accordance with a circuit design by activating, inhibiting, binding or converting reactions to form a fully connected network of interacting components, the GVR genetic circuit comprises

a mammalian Gas Vesicle Reporting Molecular Component (GVRMC) of claim 13 in a configuration in which the GV proteins are expressed and a gas vesicle (GV) type is provided when the genetic circuit operates according to the circuit design.

15. A genetically engineered isolated mammalian cell comprising the Gas Vesicle expression system (GVES) of claim 1 , configured for expression in the genetically engineered mammalian cell.

16. A genetically engineered non-human mammalian host comprising the Gas Vesicle expression system (GVES) of claim 1 , configured for expression in a mammalian cell of the genetically engineered non-human mammalian host.

17. A method to express a Gas Vesicle in a mammalian cell, the method comprising

introducing into the mammalian cell a genetically engineered Gas Vesicle expression system (GVES) of claim 1 , for a time and under condition to allow expression of the gvp genes and production of the Gas vesicle type in the mammalian cell.

18. A method to provide a gas vesicle in a mammalian host comprising

introducing into a cell of the mammalian host the genetically engineered Gas Vesicle expression system (GVES) of claim 1 , the introducing performed for a time and under condition to allow expression of the GV proteins and the production of the Gas vesicle type in the mammalian cell.

19. A method to provide a genetically engineered mammalian cell comprising a GVR genetic circuit, the method comprising:

genetically engineering the mammalian cell to introduce into the mammalian cell one or more genetically engineered Gas Vesicle Reporting Molecular Components (GVRMC) of claim 13 comprising a gas vesicle reporting (GVR) target region configured to be activated and/or inhibited by a molecular component of the GVR genetic circuit, to provide a Gas Vesicle Reporting Genetic Circuit (GVRGC).

20. A method to image a biochemical event in a mammalian cell comprised in an imaging target site, the method comprising:

introducing into the mammalian cell a Gas Vesicle Reporting Molecular Component (GVRMC) of claim 13 to provide a GVR genetic circuit in which an expression of the GV type or an intracellular spatial translocation of the GV type occurs when the GVR genetic circuit operates according to the circuit design in response to the biochemical event,

the introducing performed for a time and under conditions allowing expression of the GV protein and production of the GV type or an intracellular spatial translocation of the GV type in response to the biochemical event; and

imaging the target site comprising the mammalian host by applying a magnetic field and/or ultrasound to obtain an MRI and/or an ultrasound image of the target site.

21. A method to label a target mammalian host, the method comprising:

introducing into the mammalian cell a Gas Vesicle Reporting Molecular Component (GVRMC) of claim 13 to provide a GVR genetic circuit in which an expression of the GV type or an intracellular spatial translocation of the GV type occurs when the GVR genetic circuit operates according to the circuit design in response to a trigger molecular component;

wherein, the introducing is performed under conditions resulting in presence of the trigger molecular component in the target mammalian host.