RESUMO
An automated liquid handling system for dispensing liquid samples of sub-microliter volume has been developed. The system has eight nozzles composed of glass capillaries connected to syringe-style pumps. The distance between the nozzles can be changed from 4.5 to 9 mm, which corresponds to the distance between the wells in 96- and 384-well microplates, respectively. The eight nozzles of the system can aspirate and dispense liquid samples in both 96- and 384-well microplates. Sub-microliter volumes of reagents and samples were transferred between 96- and 384-well microplates using the system. This system was successfully used for PCR sample preparation.
RESUMO
Paraspeckle protein 1 (PSP1) in humans is a recently identified component protein of a novel nuclear body, paraspeckle. The protein has a DBHS (Drosophila behavior, human splicing) motif that is found in PSF and p54(nrb)/NonO proteins. These DBHS-containing proteins have been reported to be involved in various nuclear events such as DNA replication, transcription, and mRNA processing. Here we show that mouse paraspeckle protein 1 (mPSP1; encoded by the Pspc1 gene) has two isoforms with different C-termini lengths. Abundant expression of the longer isoform (mPSP1-alpha) and the shorter one (mPSP1-beta) were observed in testis and kidney, respectively. Transiently expressed mPSP1-alpha was localized in nuclei, but mPSP1-beta was localized in both nuclei and cytoplasm. These observations suggest that alternative splicing regulates tissue distribution and subcellular localization. Like other DBHS-containing proteins, mPSP1 has RNA-binding activity. In mouse testis, mPSP1-alpha was found in the nuclear matrix fraction. Furthermore, by coimmunoprecipitation, we confirmed that mPSP1 interacts with other DBHS-containing proteins, PSF and p54(nrb)/NonO. Therefore, we conclude that mPSP1 may regulate multiple phases of important nuclear events during spermatogenesis.