Mouse Usp42, a novel ubiquitin specific protease gene, was isolated from mouse embryonic stem cells. It consists of 1,324 amino acids with a predicted molecular weight of 146 kDa and contains the conserved Cys, Asp (I), His and Asn/Asp (II) domains defined as one of characteristics for deubiquitinating enzymes. RT-PCR analysis showed that the Usp42 transcript is expressed in NIH3T3 cells, B- and T-lymphocytes, and L1210 cells. Northern blot analysis revealed that Usp42 is expressed mainly in brain, lung, thymus and testis, and at mouse E10.5 the most during embryonic development. Usp42 expression rises from 2 weeks after birth to round-spermatid stage and decreases from condensing-spermatid stage during spermatogenesis. Deubiquitinating enzyme assays demonstrated that Usp42 can cleave ubiquitin from ubiquitinated substrates in vitro and in vivo. Taken all together, it is suggested that Usp42 is one of typical deubiquitinating enzymes, which may play an important role in mouse embryogenesis and spermatogenesis.
- Protein degradation
- Ubiquitin specific protease