Modulating xrn1

(canceled)

The method of claim 16, wherein the method is performed to treat a disease and wherein a therapeutically effective amount of said modulator of XRN1 is administered to said subject.

The method of claim 16, wherein the modulator of XRN1 is a small molecule.

The method of claim 16, wherein the modulator of XRN1 is an antibody.

The method of claim 16, wherein the modulator of XRN1 is an agonist.

The method of claim 16, wherein the modulator of XRN1 is an inhibitor of XRN1.

The method of any claim 16, wherein the subject is a mammal.

(canceled)

(canceled)

A method for the identification of a substance that modulates the expression of XRN1 and/or its biological activity, which method comprises the steps of:

• (i) contacting a XRN1 polypeptide or a fragment thereof having the biological activity of XRN1, a polynucleotide encoding such a polypeptide or polypeptide fragment, an expression vector comprising such a polynucleotide or a cell comprising such an expression vector, and a test substance under conditions that in the absence of the test substance would permit XRN1 expression and/or biological activity;
• and
• (ii) determining the amount of expression and/or biological activity of XRN1, e.g. the degradation of mature miRNA, to determine whether the test substance modulates biological activity and/or expression of XRN1, wherein a test substance which modulates biological activity and/or expression of the XRN1 is a potential therapeutical agent to treat cancer.

(canceled)

A method of modulating miRNA in a subject, the method comprising administering an effective amount of a modulator of XRN1 to said subject.

A method of modulating the efficiency of RNAi activity in a sample, the method comprising contacting the sample with a modulator of XRN1 and/or XRN2.