Abstract: Provided herein are methods and compositions for the regulation of microRNA processing. The invention presents methods for inhibiting the activity of a Lin-28-like polypeptide and methods for treating a subject with cancer comprising administering to a subject with cancer a compound that inhibits the activity of a Lin-28-like polypeptide. Compositions comprise isolated polynucleotides and expression cassettes comprising the same that promote the processing of at least one of a regulated primary microRNA transcript by Drosha and a regulated precursor microRNA by Dicer when introduced into or expressed in a cell. Compositions and methods are also provided for the selective suppression of target polynucleotides by a microRNA based on the level of expression of a Lin-28-like polypeptide within a cell.

Abstract: The present invention provides a vector system that includes a set of shuttle vectors and a docking vector such that individual DNA segments, including large segments of coding DNA, can be cloned into individual shuttle vectors in the desired orientation and combined in a desired order and orientation, into a single docking vector. The docking vector can serve as a transformation vehicle directly or as a starting point from which the entire combination can be transferred to other transformation means.