USRE37411E1 - Expression cassette for antisense expression of ribozyme - Google Patents

Expression cassette for antisense expression of ribozyme Download PDF

Info

Publication number
USRE37411E1
USRE37411E1 US09/089,594 US8959498A USRE37411E US RE37411 E1 USRE37411 E1 US RE37411E1 US 8959498 A US8959498 A US 8959498A US RE37411 E USRE37411 E US RE37411E
Authority
US
United States
Prior art keywords
ribozyme
expression
loop region
antisense
promotor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US09/089,594
Inventor
Andre Lieber
Michael Strauss
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Max Planck Gesellschaft zur Foerderung der Wissenschaften eV
Original Assignee
Max Planck Gesellschaft zur Foerderung der Wissenschaften eV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Max Planck Gesellschaft zur Foerderung der Wissenschaften eV filed Critical Max Planck Gesellschaft zur Foerderung der Wissenschaften eV
Priority to US09/089,594 priority Critical patent/USRE37411E1/en
Application granted granted Critical
Publication of USRE37411E1 publication Critical patent/USRE37411E1/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
    • C12N15/00—Mutation or genetic engineering; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification; Use of hosts therefor
    • C12N15/09—Recombinant DNA-technology
    • C12N15/11—DNA or RNA fragments; Modified forms thereof; Non-coding nucleic acids having a biological activity
    • C12N15/113—Non-coding nucleic acids modulating the expression of genes, e.g. antisense oligonucleotides; Antisense DNA or RNA; Triplex- forming oligonucleotides; Catalytic nucleic acids, e.g. ribozymes; Nucleic acids used in co-suppression or gene silencing
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
    • C07K14/435—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans
    • C07K14/575—Hormones
    • C07K14/61—Growth hormone [GH], i.e. somatotropin

Definitions

  • the present invention relates to a vector for the antisense and for the ribozyme expression.
  • the invention can be usefully employed in molecular biology, genetic engineering, and in medical applications.
  • RNA inactivation by antisense molecules or by ribozymes appears to be implementable. Both classes of compounds can be synthesized chemically or produced in conjunction with a promotor by biological expression in vitro or even in vivo.
  • RNA molecules with ribozyme activity The principle of catalytic self-cleavage of RNA molecules and the cleavage in trans has become well established in the last 10 years.
  • the hammerhead ribozymes are characterized best among the RNA molecules with ribozyme activity. Since it was shown that hammerhead structures can be integrated into heterologous RNA sequences and that ribozyme activity can thereby be transferred to these molecules, it seems clear that catalytic antisense sequences for almost any target sequence can be created, provided the target sequence contains a potential matching cleavage site.
  • RNA which contains the GUC (or CUC) triplet
  • GUC GUC
  • CUC CUC
  • Molecules of this type were synthesized for numerous target sequences. They showed catalytic activity in vitro and in some cases also in vivo. The best results were obtained with short ribozymes and target sequences.
  • a topical challenge for the in vivo application is the construction of ribozyme genes which permit a continuous expression of the ribozyme in a particular cell (Bertrand, E. et al., (1994) Nucleic Acids Res. 22, 293 to 300).
  • the mRNA substrate exists within the cell presumably in a highly folded structure, which furthermore can also be protected by proteins bound to parts of the structure.
  • the encountering of accessible sites within the substrate allowing for hybridization with the complementary flanking regions of the ribozyme is a question of actual probability.
  • Computer-aided predictions of possible, thermodynamically stable secondary structures can be useful when searching for loop regions without base pairing.
  • the physiological relevance of these conformation models is still uncertain.
  • the ribozyme Since the target mRNA is transported immediately out of the cell nucleus, the ribozyme must also enter the cytoplasm, preferably along the same path. It is, however, difficult to achieve a co-localization of ribozyme and its substrate.
  • ribozymes require the insertion of ribozyme genes in suitable expression cassettes.
  • the transcription of these constructs can produce mRNAs, in which the central, catalytic, secondary structure of the ribozymes is displaced by other, more stable base pairings within the non-complementary flanking sequences.
  • RNA level 100- to 1,000-fold excess of ribozyme molecules relative to the target sequence is necessary for attaining a recordable increase in the RNA level.
  • the production of 10 5 to 10 6 ribozymes per cell over a long period of time can, however, have cytotoxic effects. In general, such high expression levels are not stable.
  • An excess of ribozymes is needed because of the inadequate stability of the ribozymes in the presence of nucleases, because of the ineffective transport to the cytoplasm and because of the less than optimum conversion factor of the cleavage reaction.
  • the kinetics of the cleavage reaction and the ability of the ribozymes to carry out multiple conversion reactions depends on the binding parameters and the structure of the complementary flanking regions of the ribozymes.
  • Cellular proteins can affect the catalysis of the cleavage reaction, probably with the help of the dissociation of the ribozyme from the substrate of the cleavage reaction, which represents the preliminary step of the next cleavage reaction.
  • Despite many efforts to construct specific ribozyme genes generally only partial successes have been achieved, mostly on the basis of trial and error experimentation.
  • the vector shall be able to result in a continuous and stable expression of a particular desired ribozyme or an antisense sequence in a cell.
  • the expression cassette of the present invention which has a strong promotor, suitably a T7 promotor, an adenoviral va-RNA gene, a stable loop region, and an insertion site for the antisense/ribozyme sequence in the loop region.
  • FIG. 1 shows the vaRNA genes, and the labelled parts show (D) the promotor, (E) the stable loop-region, and (F) the insertion site AatII of the loop region within the va-RNA, and (G) the Pstl and SALI sites in the loop region wherein the ribozymes that are to be expressed are cloned (Seq. ID. No. 2).
  • FIG. 2 shows the result of cleavage of hGH RNA (Seq. ID. No. 3) in vitro by a ribozyme, and the labelled parks A, B and C are described below.
  • FIG. 1 shows the va-RNA gone at the site AatII into which the synthetic loop region was cloned.
  • the ribozymes that are to be expressed are cloned between the PstI and SALI sites in the loop region.
  • the symbolic box over the AatII site represents the sequence of the loop region, which is shown in the lower, right of FIG. 1 (open for the acceptance of ribozyme).
  • the T7 promotor is suitably used in combination with T7 polymerase.
  • the loop region is in a restriction site in the central part of the adenoviral va-RNA gene and its size is at least 2 ⁇ 21 bases of identical sequence.
  • a suitable base sequence of the loop region is 5′-AACCCAGGTGTGCGACGTCAG-3′ (Seq. Id. No. 1).
  • hGH RNA was synthesized from a linear (SstI section) of genomic hGH gene (1663 nt) by in vitro transcription with T7 RNA polymerase (with 0.2 ⁇ Ci 32 P of CTP/ ⁇ g of RNA). An equimolar mixture (100 nM) of ribozyme and substrate was incubated at 37° C. in 50 mM of Tris-HCl of pH 7.5 and 10 mM of magnesium chloride for 30 minutes with prior heat denaturation (90 seconds at 95° C.).
  • RNAs were purified and separated individually on a 6% polyacrylamide gel. Full-length RNA and ribozyme cleavage products (988 nt and 675 nt) were detected. The result shows that the embedding of the catalytic hammerhead structure in a stabilizing RNA (va) leads to a stable ribozyme, capable of functioning, only after the additional incorporation of the loop region.

Landscapes

  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Genetics & Genomics (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Biomedical Technology (AREA)
  • Zoology (AREA)
  • Molecular Biology (AREA)
  • Biochemistry (AREA)
  • Biotechnology (AREA)
  • Wood Science & Technology (AREA)
  • Biophysics (AREA)
  • Bioinformatics & Cheminformatics (AREA)
  • General Health & Medical Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Endocrinology (AREA)
  • Gastroenterology & Hepatology (AREA)
  • Physics & Mathematics (AREA)
  • Toxicology (AREA)
  • Plant Pathology (AREA)
  • Proteomics, Peptides & Aminoacids (AREA)
  • Microbiology (AREA)
  • Medicinal Chemistry (AREA)
  • Micro-Organisms Or Cultivation Processes Thereof (AREA)
  • Enzymes And Modification Thereof (AREA)
  • Medicines That Contain Protein Lipid Enzymes And Other Medicines (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)

Abstract

The invention is an expression cassette for the antisense expression of ribozyme, having a strong promotor, suitably a T7 promotor, an adenoviral va-RNA gene, a stable loop region, and an insertion site for the antisense/ribozyme sequence in the loop region.

Description

FIELD OF THE INVENTION
The present invention relates to a vector for the antisense and for the ribozyme expression. The invention can be usefully employed in molecular biology, genetic engineering, and in medical applications.
BACKGROUND OF THE INVENTION
The inactivation of gene functions by reverse genetic material is the most important methods for switching off certain genes. This is of great importance for combating infectious and other diseases (including AIDS), caused by interference with gene expression. A gene function can be inactivated on various levels: by homologous recombination at the DNA level, by antisense nucleic acids or ribozymes on the RNA level, or by antibodies on the protein level. In conversion to practice, all four possibilities have advantages and disadvantages. For therapeutic applications, only the RNA inactivation by antisense molecules, or by ribozymes appears to be implementable. Both classes of compounds can be synthesized chemically or produced in conjunction with a promotor by biological expression in vitro or even in vivo. The principle of catalytic self-cleavage of RNA molecules and the cleavage in trans has become well established in the last 10 years. The hammerhead ribozymes are characterized best among the RNA molecules with ribozyme activity. Since it was shown that hammerhead structures can be integrated into heterologous RNA sequences and that ribozyme activity can thereby be transferred to these molecules, it seems clear that catalytic antisense sequences for almost any target sequence can be created, provided the target sequence contains a potential matching cleavage site.
The basic principle of constructing ribozymes is very simple. An interesting region of the RNA, which contains the GUC (or CUC) triplet, is selected. Two oligonucleotides strands, each with 6 to 8 nucleotides, are taken and the catalytic hammerhead sequence is inserted between them.
Molecules of this type were synthesized for numerous target sequences. They showed catalytic activity in vitro and in some cases also in vivo. The best results were obtained with short ribozymes and target sequences. A topical challenge for the in vivo application is the construction of ribozyme genes which permit a continuous expression of the ribozyme in a particular cell (Bertrand, E. et al., (1994) Nucleic Acids Res. 22, 293 to 300).
There are five possible reasons for interference with a satisfactory functioning of expressed ribozymes within the complex intracellular milieu.
1. The mRNA substrate exists within the cell presumably in a highly folded structure, which furthermore can also be protected by proteins bound to parts of the structure. The encountering of accessible sites within the substrate allowing for hybridization with the complementary flanking regions of the ribozyme is a question of actual probability. Computer-aided predictions of possible, thermodynamically stable secondary structures can be useful when searching for loop regions without base pairing. However, the physiological relevance of these conformation models is still uncertain.
2. Since the target mRNA is transported immediately out of the cell nucleus, the ribozyme must also enter the cytoplasm, preferably along the same path. It is, however, difficult to achieve a co-localization of ribozyme and its substrate.
3. The in vivo use of ribozymes requires the insertion of ribozyme genes in suitable expression cassettes. The transcription of these constructs can produce mRNAs, in which the central, catalytic, secondary structure of the ribozymes is displaced by other, more stable base pairings within the non-complementary flanking sequences.
4. 100- to 1,000-fold excess of ribozyme molecules relative to the target sequence is necessary for attaining a recordable increase in the RNA level. The production of 10 5 to 10 6 ribozymes per cell over a long period of time can, however, have cytotoxic effects. In general, such high expression levels are not stable. An excess of ribozymes is needed because of the inadequate stability of the ribozymes in the presence of nucleases, because of the ineffective transport to the cytoplasm and because of the less than optimum conversion factor of the cleavage reaction.
5. The kinetics of the cleavage reaction and the ability of the ribozymes to carry out multiple conversion reactions depends on the binding parameters and the structure of the complementary flanking regions of the ribozymes. Cellular proteins can affect the catalysis of the cleavage reaction, probably with the help of the dissociation of the ribozyme from the substrate of the cleavage reaction, which represents the preliminary step of the next cleavage reaction. Until now, it has not been possible to predict the optimum structure of the flanking regions for a ribozyme, to guarantee high specificity and high conversion. Despite many efforts to construct specific ribozyme genes, generally only partial successes have been achieved, mostly on the basis of trial and error experimentation.
DESCRIPTION OF THE INVENTION
It is an object of the present invention to construct a vector for antisense expression and ribozyme expression. The vector shall be able to result in a continuous and stable expression of a particular desired ribozyme or an antisense sequence in a cell.
This objective is realized with the construction of the expression cassette of the present invention, which has a strong promotor, suitably a T7 promotor, an adenoviral va-RNA gene, a stable loop region, and an insertion site for the antisense/ribozyme sequence in the loop region.
DESCRIPTION OF THE DRAWINGS
The present invention is described below in detail with reference being had to the drawing, wherein:
FIG. 1 shows the vaRNA genes, and the labelled parts show (D) the promotor, (E) the stable loop-region, and (F) the insertion site AatII of the loop region within the va-RNA, and (G) the Pstl and SALI sites in the loop region wherein the ribozymes that are to be expressed are cloned (Seq. ID. No. 2).
FIG. 2 shows the result of cleavage of hGH RNA (Seq. ID. No. 3) in vitro by a ribozyme, and the labelled parks A, B and C are described below.
Thus, FIG. 1 shows the va-RNA gone at the site AatII into which the synthetic loop region was cloned. The ribozymes that are to be expressed are cloned between the PstI and SALI sites in the loop region. The symbolic box over the AatII site represents the sequence of the loop region, which is shown in the lower, right of FIG. 1 (open for the acceptance of ribozyme).
DETAILED DESCRIPTION OF THE INVENTION
The T7 promotor is suitably used in combination with T7 polymerase. The loop region is in a restriction site in the central part of the adenoviral va-RNA gene and its size is at least 2×21 bases of identical sequence. A suitable base sequence of the loop region is 5′-AACCCAGGTGTGCGACGTCAG-3′ (Seq. Id. No. 1).
The cleavage results of FIG. 2 also show
(A) the structure of the specific ribozyme for a 27 n.t. region about the GUC at position 988 within the exon IV of hGH RNA;
(B) the maps of plasmid matrices for ribozyme synthesis by in vitro transcription with pol III (HeLa extract) and T7 RNA polymerase; and
(C) an electrophoretic representation of the cleavage products.
The invention is further described by the following specific example.
EXAMPLE
The T7Rz and T7Rzneo plasmids were linearized by a Hind III treatment. GvaRz and GvaLRz were used in circular form. hGH RNA was synthesized from a linear (SstI section) of genomic hGH gene (1663 nt) by in vitro transcription with T7 RNA polymerase (with 0.2 μCi32P of CTP/μg of RNA). An equimolar mixture (100 nM) of ribozyme and substrate was incubated at 37° C. in 50 mM of Tris-HCl of pH 7.5 and 10 mM of magnesium chloride for 30 minutes with prior heat denaturation (90 seconds at 95° C.). After the cleavage, the RNAs were purified and separated individually on a 6% polyacrylamide gel. Full-length RNA and ribozyme cleavage products (988 nt and 675 nt) were detected. The result shows that the embedding of the catalytic hammerhead structure in a stabilizing RNA (va) leads to a stable ribozyme, capable of functioning, only after the additional incorporation of the loop region.
3 21 base pairs nucleic acid single linear rRNA not provided 1 AACCCAGGTG TGCGACGTCA G 21 40 base pairs nucleic acid single linear rRNA not provided 2 GGTTACCGCC CGCGTGTCGA ACCCAGGTGT GCGACGTCAG 40 28 base pairs nucleoside base single linear DNA (genomic) not provided 3 UCCUCAGGAG UGGUCUUCGC CAACAGCC 28

Claims (5)

We claim:
1. An antisense and ribozyme expression cassette which comprises a strong promotor, an adenoviral va-RNA gene having a central part, a stable loop region of a size of at least 2×21 base pairs of identical sequences, and an insertion site for the antisense/ribozyme sequence in the loop region, wherein said promotor, the adenoviral va-RNA gene, the loop region, and the insertion site are linked as shown in FIG. 1.
2. The expression cassette of claim 1, wherein said promotor is a T7 promotor.
3. The expression cassette of claim 2, wherein the T7 promotor is employed in combination with a T7 polymerase.
4. The expression cassette of claim 1, wherein said loop region is in a restriction site in the central part of the adenoviral va-RNA gene.
5. The expression cassette of claim 1, wherein said loop region contains twice the base sequence 5′-AACCCAGGTGTGCGACGTCAG-3′ (Seq. Id. No. 1).
US09/089,594 1994-07-04 1998-06-02 Expression cassette for antisense expression of ribozyme Expired - Fee Related USRE37411E1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US09/089,594 USRE37411E1 (en) 1994-07-04 1998-06-02 Expression cassette for antisense expression of ribozyme

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE4424761A DE4424761C1 (en) 1994-07-04 1994-07-04 Expression cassette for continuous, stable prodn. of ribozyme
DE4424761 1994-07-04
US08/314,588 US5695992A (en) 1994-07-04 1994-09-28 Expression cassette for antisense expression of ribozyme
US09/089,594 USRE37411E1 (en) 1994-07-04 1998-06-02 Expression cassette for antisense expression of ribozyme

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US08/314,588 Reissue US5695992A (en) 1994-07-04 1994-09-28 Expression cassette for antisense expression of ribozyme

Publications (1)

Publication Number Publication Date
USRE37411E1 true USRE37411E1 (en) 2001-10-16

Family

ID=25938313

Family Applications (2)

Application Number Title Priority Date Filing Date
US08/314,588 Ceased US5695992A (en) 1994-07-04 1994-09-28 Expression cassette for antisense expression of ribozyme
US09/089,594 Expired - Fee Related USRE37411E1 (en) 1994-07-04 1998-06-02 Expression cassette for antisense expression of ribozyme

Family Applications Before (1)

Application Number Title Priority Date Filing Date
US08/314,588 Ceased US5695992A (en) 1994-07-04 1994-09-28 Expression cassette for antisense expression of ribozyme

Country Status (4)

Country Link
US (2) US5695992A (en)
EP (1) EP0767834A1 (en)
DE (1) DE4424761C1 (en)
WO (1) WO1996001315A1 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6130092A (en) * 1994-07-04 2000-10-10 Max-Planck Gesellschaft Zur Forderung Der Wissenschaften E.V. Ribozyme gene library and method for making
US6107027A (en) * 1994-12-14 2000-08-22 University Of Washington Ribozymes for treating hepatitis C
FR2743818B1 (en) * 1996-01-23 1998-04-10 Agronomique Inst Nat Rech DNA CONSTRUCTS AND EXPRESSION VECTORS DERIVED FROM THE VA RNA GENE OF ADENOVIRUS
GB9912965D0 (en) * 1999-06-03 1999-08-04 Oxford Biomedica Ltd In vivo selection method
DE10046913A1 (en) * 2000-09-21 2002-04-18 Nascacell Gmbh Expression system for functional nucleic acids
US8252527B2 (en) * 2007-02-16 2012-08-28 The Research Foundation Of State University Of New York Method for identification of polynucleotides capable of cleaving target mRNA sequences

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ATE140961T1 (en) * 1989-03-16 1996-08-15 Boehringer Ingelheim Int GENETIC UNITS FOR INHIBITING THE FUNCTION OF RNA
FR2687411A1 (en) * 1992-02-13 1993-08-20 Nice Sophia Antipolis Universi Vector comprising a viral gene transcribed by RNA polymerase III, and process for the intercellular production of RNA

Also Published As

Publication number Publication date
EP0767834A1 (en) 1997-04-16
WO1996001315A1 (en) 1996-01-18
DE4424761C1 (en) 1995-06-08
US5695992A (en) 1997-12-09

Similar Documents

Publication Publication Date Title
Lieber et al. Selection of efficient cleavage sites in target RNAs by using a ribozyme expression library
US5916808A (en) Antisense oligonucleotides which combat aberrant splicing and methods of using the same
JP2022078083A (en) Guide rna with chemical modifications
US5565350A (en) Compounds and methods for site directed mutations in eukaryotic cells
JP4321877B2 (en) Therapeutic molecules produced by trans-splicing
US5272065A (en) Regulation of gene expression by employing translational inhibition of MRNA utilizing interfering complementary MRNA
KR102641298B1 (en) Lipocationic dendrimers and uses thereof
JP2006311864A (en) Regulatable nucleic acid therapeutic and method of use thereof
CA2771228A1 (en) Treatment of 'c terminus of hsp70-interacting protein' (chip) related diseases by inhibition of natural antisense transcript to chip
JPH07508656A (en) Formation of pseudo-half-knot RNA by hybridization of antisense oligonucleotide to target RNA secondary structure
AU2006317222B2 (en) DNA constructs for specific inhibition of gene expression by RNA interference
US5405775A (en) Retrons coding for hybrid DNA/RNA molecules
US6040159A (en) TNF-α ribozymes and derivatives capable of decreasing degradation of MRNA in vivo
US6921816B2 (en) Chimerical peptide-nucleic acid fragment, process for producing the same and its for appropriately introducing nucleic acids into cell organelles and cells
USRE37411E1 (en) Expression cassette for antisense expression of ribozyme
Egli et al. Synthetic oligonucleotides as RNA mimetics: 2′-modified RNAs and N3′→ P5′ phosphoramidates
US6310047B1 (en) High affinity DNA binding compounds as adjuvants in antisense technology
WO1997040060A1 (en) Ribosomes as vectors for rna
US5912149A (en) Multimeric self-cleaving ribozyme
AU784832B2 (en) Self-cleaving RNA sequences and their use for the control of protein synthesis
US5864028A (en) Degradation resistant mRNA derivatives linked to TNF-α ribozymes
Pascolo et al. Relative contribution of photo-addition, helper oligonucleotide and RNase H to the antisense effect of psoralen-oligonucleotide conjugates, on in vitro translation of Leishmania mRNAs
US7148044B1 (en) Nucleic acid enzyme for RNA cleavage
KR100385904B1 (en) Methods preparing antisense-molecules using bacteriophages with closed single stranded genome and novel antisense-molecules produced thereby
COHEN Selective anti-gene therapy for cancer: principles and prospects

Legal Events

Date Code Title Description
REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees