Mouse nuclear myosin I knock-out shows interchangeability and redundancy of myosin isoforms in the cell nucleus

0423205 - ÚMG 2014 RIV US eng J - Článek v odborném periodiku
Venit, Tomáš - Dzijak, Rastislav - Kalendová, Alžběta - Kahle, Michal - Rohožková, Jana - Schmidt, V. - Rülicke, T. - Rathkolb, B. - Hans, W. - Bohla, A. - Eickelberg, O. - Stoeger, T. - Wolf, E. - Yildirim, A.Ö. - Gailus-Durner, V. - Fuchs, H. - de Angelis, M.H. - Hozák, Pavel
Mouse nuclear myosin I knock-out shows interchangeability and redundancy of myosin isoforms in the cell nucleus.
PLoS ONE. Roč. 8, č. 4 (2013), e61406. ISSN 1932-6203. E-ISSN 1932-6203
Grant CEP: GA ČR GAP305/11/2232; GA TA ČR TE01020022; GA MŠMT LH12143; GA ČR(CZ) GD204/09/H084
Výzkumný záměr: CEZ:AV0Z50520514
Institucionální podpora: RVO:68378050
Klíčová slova: nuclear myosin * myosin isoforms * cell nucleus
Kód oboru RIV: EB - Genetika a molekulární biologie
Impakt faktor: 3.534, rok: 2013

Nuclear myosin I (NM1) is a nuclear isoform of the well-known “cytoplasmic” Myosin 1c protein (Myo1c). Located on the 11th chromosome in mice, NM1 results from an alternative start of transcription of the Myo1c gene adding an extra 16 amino acids at the N-terminus. Previous studies revealed its roles in RNA Polymerase I and RNA Polymerase II transcription, chromatin remodeling, and chromosomal movements. Its nuclear localization signal is localized in the middle of the molecule and therefore directs both Myosin 1c isoforms to the nucleus. In order to trace specific functions of the NM1 isoform, we generated mice lacking the NM1 start codon without affecting the cytoplasmic Myo1c protein. Mutant mice were analyzed in a comprehensive phenotypic screen in cooperation with the German Mouse Clinic. Strikingly, no obvious phenotype related to previously described functions has been observed. However, we found minor changes in bone mineral density and the number and size of red blood cells in knock-out mice, which are most probably not related to previously described functions of NM1 in the nucleus. In Myo1c/NM1 depleted U2OS cells, the level of Pol I transcription was restored by overexpression of shRNA-resistant mouse Myo1c. Moreover, we found Myo1c interacting with Pol II. The ratio between Myo1c and NM1 proteins were similar in the nucleus and deletion of NM1 did not cause any compensatory overexpression of Myo1c protein. We observed that Myo1c can replace NM1 in its nuclear functions. Amount of both proteins is nearly equal and NM1 knock-out does not cause any compensatory overexpression of Myo1c. We therefore suggest that both isoforms can substitute each other in nuclear processes.
Trvalý link: http://hdl.handle.net/11104/0229365