Functional arrays for high throughput characterization of gene expression regulatory elements

• US 20070161031A1
• Filed: 12/07/2006
• Published: 07/12/2007
• Est. Priority Date: 12/16/2005
• Status: Abandoned Application

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Inventors: Myers, Richard, Trinklein, Nathan, Cooper, Sara, Aldred, Shelley
• Application Number:
  US11/636,385
• Publication Number:
  US 20070161031A1
• Time in Patent Office: Days
• US Class Current: 435/6
• CPC Class Codes: C12N 15/1086 Preparation or screening of expression libraries, e.g. reporter assays
• CPC Class Codes: C12Q 1/6897 involving reporter genes operably linked to promoters

Abstract

The present invention provides compositions, kits, assemblies, libraries, arrays, and high throughput methods for large scale structural and functional characterization of gene expression regulatory elements in a genome of an organism, especially in a human genome. In one aspect of the invention, an array of expression constructs is provided, each of the expression constructs comprising: a nucleic acid segment operably linked with a reporter sequence in an expression vector such that expression of the reporter sequence is under the transcriptional control of the nucleic acid segment, the nucleic acid segment varying in the library and having a diversity of at least 50. The nucleic acid segments can be a large library of gene expression regulatory elements such as transcriptional promoters. The present invention can have a wide variety of applications such as in personalized medicine, pharmacogenomics, and correlation of polymorphisms with phenotypic traits.

Claims

1. A library of expression constructs, each member of the library comprising a different nucleic acid segment from a genome, wherein the segment comprises transcription regulatory sequences, operably linked with a heterologous reporter sequence in an expression vector such that expression of the reporter sequence is under transcriptional control of the transcription regulatory sequences, wherein:

(a) the library has a diversity of at least 50 different nucleic acid segments;

(b) each nucleic acid segment and is naturally linked in the genome with a sequence expressed as a cDNA; and

(c) the average length of the nucleic acid segments in the library is at least 600 nucleotides.

2. The library of claim 1, wherein the average length of the nucleic acid segments in the library is between 700 nucleotides and 1200 nucleotides.

3. The library of claim 1, wherein the average length of the nucleic acid segments in the library is between 800 nucleotides and 1100 nucleotides.

4. The library of claim 1, wherein at least 90% of the nucleic acid segments in the library have a length between 700 nucleotides and 1300 nucleotides.

5. The library of claim 1, wherein each nucleic acid segment comprises at least 500 nucleotides upstream of a transcriptional start site.

6. The library of claim 1, wherein no more than 5% of the nucleic acid segments are naturally linked to cDNA alignment artifacts.

7. The library of claim 1, wherein the library is indexed to indicate the gene naturally under the transcriptional control of each transcription regulatory sequence in the genome.

8. The library of claim 1, wherein the reporter sequences encode the same reporter molecule.

9. The library of claim 1, wherein the reporter sequence encodes a light-emitting reporter molecule, a fluorescent reporter molecule or a calorimetric molecule.

10. The library of claim 1, wherein each reporter sequence comprises a pre-determined, unique nucleotide barcode and/or a reporter that reports a visible signal.

11. The library of claim 1, wherein the genome is a mammalian genome.

12. The library of claim 1, wherein the genome is a human genome.

13. The library of claim 1, wherein the genome is a mouse genome.

14. The library of claim 1, wherein the diversity of the nucleic acid segment is at least 100.

15. The library of claim 1, wherein the diversity of the nucleic acid segment is at least 500.

16. The library of claim 1, wherein the expression construct is a plasmid or viral construct.

17. The library of claim 1, wherein the nucleic acid segments include at least two of the DNA segments selected from the group consisting of SEQ ID NOs:

1-45096 or fragments thereof or nucleic acids having sequences with at least 70%, 75%, 80%, 85%, 90%, 95%, or 98% homology thereto.

71. A business method comprising:

(a) commercializing the compositions, devices or methods of any of claims 1, 18, 19, 22, 25, 28, 34, 38, 43, 45, 46, 52, 54, 57, 62, 63 and 64.

18. A library of isolated nucleic acid molecules, each member of the library comprising a different, pre-determined nucleic acid segment from a genome, wherein the segment comprises transcription regulatory sequences, wherein:

(a) the library has a diversity of at least 50 different nucleic acid segments;

(b) each nucleic acid segment is naturally linked in the genome with a sequence expressed as a cDNA; and

(c) the average length of the nucleic acid segments in the library is at least 600 nucleotides.

19. A library of recombinant nucleic acid molecules, each member of the library comprising a different, determined nucleic acid segment from a genome linked with a heterologous nucleic acid molecule, wherein the segment comprises transcription regulatory sequences, wherein:

(a) the library has a diversity of at least 50 different nucleic acid segments;

(b) each nucleic acid segment is naturally linked in the genome with a sequence expressed as a cDNA; and

(c) the average length of the nucleic acid segments in the library is at least 600 nucleotides.

20. The library of claim 19 wherein the nucleic acid molecule comprises a pair of restriction sites flanking a 5′

and a 3′

side of the segment.

21. The library of claim 19 wherein the nucleic acid molecule comprises sites flanking on the 5′

and 3′

ends the segment that are complementary to PCR primers that may be used for amplification.

22. A library of cells, wherein each cell in the library of cells comprises a different member of a library of expression constructs, wherein each member of the library of expression constructs comprises a different nucleic acid segment from a genome, wherein the segment comprises transcription regulatory sequences, operably linked with a heterologous reporter sequence in an expression vector such that expression of the reporter sequence is under transcriptional control of the transcription regulatory sequences, wherein:

(a) the library has a diversity of at least 50 different nucleic acid segments;

(b) each nucleic acid segment is naturally linked in the genome with a sequence expressed as a cDNA; and

(c) the average length of the nucleic acid segments in the library is at least 600 nucleotides.

23. The library of claim 22 wherein the cells are human cells.

24. The library of claim 22 wherein the cells are non-human cells.

25. A collection of cells comprising within the cells a library of expression constructs, each member of the library of expression constructs comprising:

a different nucleic acid segment from a genome, wherein the segment comprises transcription regulatory sequences, operably linked with a different heterologous reporter sequence in an expression vector such that expression of the reporter sequence is under transcriptional control of the transcription regulatory sequences.

26. The collection of cells of claim 25, wherein the cell containing a different expression construct is in an identifiable vial or well.

27. The collection of cells of claim 25 wherein:

(a) the library has a diversity of at least 50 different nucleic acid segments;

(b) each nucleic acid segment is naturally linked in the genome with a sequence expressed as a cDNA; and

(c) the average length of the nucleic acid segments in the library is at least 600 nucleotides.

28. A device comprising at least one plate comprising a plurality of wells, each well containing a different member of a library of expression constructs, each expression construct comprising a different, nucleic acid segment from a genome, wherein the segment comprises transcription regulatory sequences, operably linked with a heterologous reporter sequence in an expression vector such that expression of the reporter sequence is under transcriptional control of the transcription regulatory sequences, and wherein each member has a known location among the wells.

29. The device of claim 28, wherein:

(a) the library has a diversity of at least 50 different nucleic acid segments,

(b) each nucleic acid segment is naturally linked in the genome with a sequence expressed as a cDNA; and

(c) the average length of the nucleic acid segments in the library is at least 600 nucleotides.

30. The device of claim 28, wherein the constructs are in the form of a dried nucleic acid or are in solution.

31. The device of claim 30 wherein the constructs are in a transfection matrix combination.

32. The device of claim 28 comprising a 96-well plate, a 384-well plate or a 1536 well plate.

33. The device of claim 28, wherein the gene expression regulatory elements include at least two of the DNA segments selected from the group consisting of SEQ ID NOs:

145096 or fragments thereof or nucleic acids having sequences with at least 70%, 75%, 80%, 85%, 90%, 95%, or 98% homology thereto.

34.

35. A device comprising at least one plate comprising a plurality of wells, each well containing a different member of the library of cells, wherein each cell in the library of cells comprises a different member of the library of expression constructs, each expression construct comprising a different nucleic acid segment from a genome, wherein the segment comprises transcription regulatory sequences, operably linked with a heterologous reporter sequence in an expression vector such that expression of the reporter sequence is under transcriptional control of the transcription regulatory sequences and wherein each member of the library of cells has a known location among the wells.

36. The device of claim 35 wherein:

(a) the library of expression constructs has a diversity of at least 50 different nucleic acid segments;

(b) each nucleic acid segment is naturally linked in the genome with a sequence expressed as a cDNA; and

(c) the average length of the nucleic acid segments in the library is at least 600 nucleotides.

44. A system comprising:

(a) a device of claim 35;

(b) a reader adapted to detect a signal from an expressed reporter sequenced in each well of the device.

45. The system of claim 44 wherein the device comprises a plurality of control constructs that provide a predetermined signal level, and wherein the system further comprises (c) software comprising:

(i) code that executes an algorithm that normalizes signal from all wells of plates based on the signal from the control constructs.

46. Software comprising code that executes the algorithm of claim 45.

48. The method of claim 45 wherein:

(i) the library has a diversity of at least 50 different nucleic acid segments;

(ii) each nucleic acid segment is naturally linked in the genome with a sequence expressed as a cDNA; and

(iii) the average length of the nucleic acid segments in the library is at least 600 nucleotides.

49. The method of claim 45 wherein the step of providing the device comprises:

(i) providing a device comprising at least one plate comprising a plurality of wells, each well containing a different member of the library of expression constructs, wherein each member of the library of expression constructs has a known location among the wells;

(ii) delivering cells to each of the wells; and

(iii) transfecting the cells with the expression constructs.

50. The method of claim 45 further comprising:

(d) perturbing the cells in each well;

(e) measuring the level of expression of the reporter sequence in each well; and

(f) determining whether the level of expression in any well changed after contacting the cells with the test compound.

51. The method of claim 50 wherein perturbing comprises contacting the cells in each well with a test compound, exposing the cells to different environmental conditions, or genetically modifying the cells either permanently or transiently such as by inducing mutation, overexpressing a transcript for example by transfecting with a cDNA or decreasing expression of a transcript by siRNA.

52. The method of claim 45 wherein the reporter sequence encodes a reporter molecule and measuring expression of the reporter sequence comprises measuring the expression of the reporter molecule.

37. A kit for characterizing a biological function of a target gene expression regulatory element, comprising:

(a) a device comprising at least one plate comprising a plurality of wells, each well containing a different member of the library of expression constructs, each expression construct comprising a different nucleic acid segment from a genome, wherein the segment comprises transcription regulatory sequences operably linked with a heterologous reporter sequence in an expression vector such that expression of the reporter sequence is under transcriptional control of the transcription regulatory sequences, and wherein each member has a known location among the wells; and

(b) reporter assay substrates.

38. The kit of claim 37, further comprising:

instructions for characterizing the biological function of the target gene expression regulatory element.

39. A device comprising a solid substrate comprising a surface and nucleic acid molecules immobilized to the surface, each at a different known location, wherein each molecule comprises a nucleotide sequence of at least 10 nucleotides from a genomic segment comprising transcription regulatory sequences and the device comprises transcription regulatory sequences from at least 50 different genomic segments.

40. The device of claim 39 wherein each nucleic acid segment is naturally linked in the genome with a sequence expressed as a cDNA.

41. The device of claim 39 wherein the gene expression regulatory elements include at least two of the DNA segments selected from the group consisting of SEQ ID NOs:

1-45096 or fragments thereof.

42. The device of claim 39 wherein the molecules are no more than 60 nucleotides long.

43. The device of claim 39 wherein each genomic segment is represented by a set comprising a plurality of molecules, each molecule in the set comprising a different a different nucleotide sequence from the genomic segment.

47. A method comprising:

(a) providing a device comprising at least one plate comprising a plurality of wells, each well containing a different member of a library of cells, wherein each cell in the library of cells comprises a different member of the library of expression constructs, each expression construct comprising a different nucleic acid segment from a genome, wherein the segment comprises transcription regulatory sequences, operably linked with a heterologous reporter sequence in an expression vector such that expression of the reporter sequence is under transcriptional control of the transcription regulatory sequences and wherein each member of the library of cells has a known location among the wells;

(b) culturing the cells; and

(c) measuring the level of expression of the reporter sequence in each well.

58. A method for evaluating the level of expression from constructs measured by the method of claim 47 comprising:

(a) providing a set of cells comprising a set of control reporter constructs, each control reporter construct comprising a random genomic fragment operatively linked with the heterologous reporter sequence;

(b) measuring the level of expression of the reporter sequence in each of cells;

(c) determining a mean or average of the expression level among the control constructs;

(d) determining, for the level of expression of each of the test constructs, a statistical distance from the mean or average; and

(e) determining whether the deviation is statistically significant.

59. The method of claim 58 wherein the deviation is a standard deviation.

60. The method of claim 58 wherein the random genomic fragments are random fragments selected from the genome of the same size distribution as the experimental fragments.

61. The method of claim 58 wherein the random genomic fragments are random fragments from middle exons of protein coding genes where the middle exon codes for protein and is a length of at least the size of the experimental fragments and at least 5,000 or 10,000 bases from a known transcription start site in the genome.

62. The method of claim 58 wherein activity and significance are calculated as a Z-score by the following equation:

Z-score promoter activity=(raw promoter activity−

mean of random controls)/standard deviation of the random controls.

63. Software comprising code that executes an algorithm that determines the mean and deviations of claim 58.

53. A method comprising:

(a) providing a first device and second device, each device comprising at least one plate comprising a plurality of wells, each well containing a different member of a library of cells, wherein each cell in the library of cells comprises a different member of the library of expression constructs, each expression construct comprising a different nucleic acid segment from a genome, wherein the segment comprises transcription regulatory sequences, operably linked with a heterologous reporter sequence in an expression vector such that expression of the reporter sequence is under transcriptional control of the transcription regulatory sequences, wherein each member of the library of cells has a known location among the wells and wherein the first and second devices comprise cells of the same type and the library of expression constructs is the same in the first and second devices;

(b) culturing the cells of the first and second devices under different culture conditions;

(c) measuring the level of expression of the reporter sequence in each well; and

(d) comparing the level of expression of the reporter sequence to each transcription regulatory sequence between the first cell type and the second cell type.

54. The method of claim 53 wherein the different culture conditions comprise culturing the cells of the second device in the presence of compound not present in the culture of the cells of the first device.

55. A method comprising:

(a) providing a first device and second device, each device comprising at least one plate comprising a plurality of wells, each well containing a different member of a library of cells, wherein each cell in the library of cells comprises a different member of the library of expression constructs, each expression construct comprising a different nucleic acid segment from a genome, wherein the segment comprises transcription regulatory sequences, operably linked with a heterologous reporter sequence in an expression vector such that expression of the reporter sequence is under transcriptional control of the transcription regulatory sequences, wherein each member of the library of cells has a known location among the wells and wherein the first device comprises cells of a first type and second device comprises cells of a second type and the library of expression constructs is the same in the first and second devices;

(b) culturing the cells of the first and second devices;

(c) measuring the level of expression of the reporter sequence in each well; and

(d) comparing the level of expression of the reporter sequence to each transcription regulatory sequence between the first cell type and the second cell type.

56. The method of claim 55 wherein:

(i) the library has a diversity of at least 50 different nucleic acid segments;

(ii) each nucleic acid segment is naturally linked in the genome with a sequence expressed as a cDNA; and

(iii) the average length of the nucleic acid segments in the library is at least 600 nucleotides.

57. The method of claim 55 wherein the step of providing the devices comprises:

(i) providing devices, each device comprising at least one plate comprising a plurality of wells, each well containing a different member of the library of expression constructs, wherein each member of the library of expression constructs has a known location among the wells;

(ii) delivering cells to each of the wells; and

(iii) transfecting or infecting the cells with the expression constructs.

64. Analysis software that integrates Z-score transformed promoter activity data with Z-score transformed functional data from DNA methylation experiments, transcription factor binding data, histone modification data, DNase hypersensitivity data, nucleosome displacement data or gene expression data.

65. A method for determining a methylation pattern in a sequence of nucleic acid comprising:

(a) creating a first set of labeled nucleic acid segments by;

(i) obtaining a nucleic acid molecule comprising the sequence from a source; and

(ii) labeling the isolated nucleic acid molecule with a first label, whereby labeling creates a first set of labeled nucleic acid segments;

(b) creating a second set of labeled nucleic acid segments by;

(i) obtaining the nucleic acid molecule having the nucleotide sequence from the source;

(ii) contacting the nucleic acid molecule with at least three methyl-sensitive restriction enzymes having different recognition sequences, wherein the enzymes cleave the nucleic acid molecule at un-methylated recognition sequences but not at methylated recognition sequences, thereby nucleic acid fragments;

(iii) isolating nucleic acid fragments of at least 100 nucleotides from the mixture; and

(iv) labeling the fragments with a second, different label, whereby labeling creates a second set of nucleic acid segments;

(c) hybridizing the first and second labeled segments to one or more nucleic acid probes comprising the nucleotide sequence; and

(d) determining areas of the nucleotide sequence that are differentially labeled by the first and second labeled segments, wherein differentially labeled areas are un-methylated areas of the nucleotide sequence.

66. The method of claim 65 wherein the nucleic acid molecule comprises transcription regulatory sequences.

67. The method of claim 65 comprising contacting the nucleic acid molecules with at least six different methyl-sensitive enzymes.

68. The method of claim 65 wherein the first label generates a first color and the second label generates a second, different color.

69. The method of claim 65 comprising hybridizing the segments to a plurality of probes that tile the nucleotide sequence of the nucleic acid molecule.

70. The method of claim 65 further comprising performing the method a second time with nucleic acid from a second source, wherein the first and second sources are healthy and diseased tissues or two different types of diseased tissues.