METHODS AND PRODUCTS FOR EXPRESSION OF MICRO RNAs

Abstract

The invention relates to microRNAs, methods of producing microRNAs and methods for using microRNAs.

We claim: 
     
         1 . A precursor microRNA molecule, comprising:
 an isolated nucleic acid comprising:   a stem-loop structure, wherein a microRNA sequence is incorporated into a stem of the stem-loop structure, and   a microRNA flanking sequence flanking at least one end of the stem-loop structure.   
     
     
         2 . The precursor microRNA molecule of  claim 1 , wherein the microRNA flanking sequence is between 40 and 2,000 nucleotides in length. 
     
     
         3 . The precursor microRNA molecule of  claim 1 , wherein the microRNA sequence and the microRNA flanking sequence are derived from the same microRNA gene. 
     
     
         4 - 5 . (canceled) 
     
     
         6 . The precursor microRNA molecule of  claim 1 , wherein the precursor microRNA molecule includes at least two stem-loop structures. 
     
     
         7 . The precursor microRNA molecule of  claim 1 , wherein the microRNA flanking sequence is between 40 and 4,000 nucleotides in length. 
     
     
         8 - 9 . (canceled) 
     
     
         10 . The precursor microRNA molecule of  claim 1 , wherein the precursor microRNA molecule has microRNA flanking sequences flanking each end of the stem-loop structure. 
     
     
         11 - 13 . (canceled) 
     
     
         14 . A method of altering the productive utilization of a target mRNA, comprising:
 contacting a cell with a vector capable of expressing a precursor microRNA of  claim 1  wherein the precursor microRNA includes a microRNA sequence capable of altering the productive utilization of the target mRNA.   
     
     
         15 . The method of  claim 14 , wherein the precursor microRNA is specific for a cancer-associated RNA. 
     
     
         16 . The method of  claim 14 , wherein the precursor microRNA is specific for a viral RNA. 
     
     
         17 . The method of  claim 14 , wherein the method is performed in vivo. 
     
     
         18 - 22 . (canceled) 
     
     
         23 . A vector for producing a precursor microRNA wherein the vector includes a sequence encoding a precursor microRNA, including a microRNA sequence and a microRNA flanking sequence, and at least one promoter element. 
     
     
         24 . The vector of  claim 23 , wherein the vector is a viral vector. 
     
     
         25 . The vector of  claim 24 , wherein the viral vector is a retroviral vector. 
     
     
         26 . The vector of  claim 23 , wherein the at least one of the promoter is an inducible promoter. 
     
     
         27 - 29 . (canceled) 
     
     
         30 . A host cell transfected with the vector of  claim 23 . 
     
     
         31 - 32 . (canceled) 
     
     
         33 . A method for modulating hematopoiesis, comprising:
 contacting a hematopoietic cell with a vector capable of expressing a precursor microRNA of  claim 1  wherein the precursor microRNA includes a microRNA sequence capable of altering accumulation of a protein involved in hematopoiesis.   
     
     
         34 . A method of making the vector of  claim 23 , the method comprising providing a vector comprising a microRNA flanking sequence and at least one promoter element, inserting a sequence encoding a stem-loop structure into the vector in the context of the microRNA flanking sequence, wherein a microRNA sequence is incorporated into a stem of the stem-loop structure. 
     
     
         35 . The method of  claim 34 , wherein the vector comprises two microRNA flanking sequences, and wherein the sequence encoding a stem-loop structure is flanked by the two microRNA flanking sequences.