Association of the mammalian helicase MAH with the pre-mRNA splicing complex

Association of the mammalian helicase MAH with the pre-mRNA splicing complex

Departments of ^*Cell Growth and Regulation, and ^‡Cellular and Molecular Biology, Dana–Farber Cancer Institute, Boston, MA 02115

Abstract

Conversion of pre-mRNAs into mature mRNAs includes several consecutive enzymatic modification steps that are carried out in the spliceosomes. Helicases have been shown to contribute to these catalytic processes both in yeast and in mammalian cells. Our results identify the mammalian protein MAH (matrix-associated helicase) as a new helicase present in the spliceosome complex. Sequence comparison describes MAH as the first higher eukaryotic member of the helicase superfamily I, with demonstrated enzymatic activity. Because MAH does not bind small nuclear ribonucleoproteins (snRNPs), it appears to be a non-snRNP binding factor of the splicing complex. In conclusion, our data suggest the involvement of MAH in processing of pre-mRNAs in mammalian cells.

Footnotes

↵ † Present address: The Population Council Center for Biomedical Research, New York, NY 10021.
↵ § Present address: Department of Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213.
↵ ¶ To whom reprint requests should be addressed at: Department of Cell Growth and Regulation, Dana–Farber Cancer Institute, 44 Binney Street, Boston, MA 02115.
Arthur B. Pardee
ABBREVIATIONS:

MAH,

matrix-associated helicase;

snRNP,

small ribonucleoprotein;

snRNA,

small nuclear RNA;

DAPI,

4′,6′-diamidino-2-phenylindole;

FITC,

fluorescein isothiocyanate