Identification and sequence analysis of prolactin receptor and its differential expression profile at various developmental stages in striped hamsters

Prolactin (PRL) plays critical roles in regulation of biological functions with the binding of specific prolactin receptor (PRLR). Revealing the expression patterns of PRLR at different developmental stages is beneficial to better understand the role of PRL and its mechanism of action in striped hamsters. In this study, the cDNA sequence of PRLR (2866-base-pairs) was harvested from the pituitary of mature female striped hamsters (Cricetulus barabensis) that contains an 834-base-pair 5′-untranslated region (1-834 bp), a 1848-base-pair open reading frame (835-2682 bp), and a 184-base-pair 3′-untranslated region (2683-2866). The 1848-base-pair open reading frame encodes a mature prolactin-binding protein of 592 amino acids. In the mature PRLR, two prolactin-binding motifs, 12 cysteines, and five potential Asn-linked glycosylation sites were detected. Our results showed that the PRLR mRNA quantity in the hypothalamus, pituitary, ovaries, or testis was developmental-stage-dependent, with the highest level at sub-adult stage and the lowest level at old stage. We also found that PRLR mRNAs were highest in pituitary, medium level in hypothalamus, and lowest in ovaries or testis. PRLR mRNAs were significantly higher in males than in females, except in the hypothalamus and pituitary from 7-week-old striped hamsters. Moreover, the PRLR mRNAs in the hypothalamus, pituitary, and ovaries or testis were positively correlated with the expression levels of GnRH in the hypothalamus. These results indicated that the PRLR has conserved domain in striped hamster, but also possesses specific character. PRLR has multiple biological functions including positively regulating reproduction in the striped hamster.

Asparagine Synthetase Is Partially Localized to the Plasma Membrane and Upregulated by L-asparaginase in U937 Cells / 华中科技大学学报（医学）（英德文版）

This study investigated the intracellular localization of asparagine synthetase (ASNS) in the relation with chemoresistance in leukemia.pIRES-GFP-ASNS-Flag/Neo expression vector was transiently tansfected into SK-N-MC cells and 297T cells respectively.Immunofluorescence and Western blot analysis were performed for cellular localization of ASNS respectively.U937 cells were treated with L-asparaginase for 48 h and examined for endogenous ASNS expression on plasma membrane by immunofluorescence staining.Immunofluorescence staining showed that the transiently expressed ASNS was partly localized on transfected-SK-N-MC cell surface.Moreover,Western blotting exhibited that ASNS expressed both in cytosol and on plasma membrane of transfected-293T cells.Immunofluo-rescence staining with anti-ASNS-specific monoclonal antibody revealed that endogenous ASNS was localized on the plasma membrane of U937 cells,except for its distribution in the cytosol.In addition,ASNS exhibited a higher expression on plasma membrane after treatment with L-asparaginase as compared with the untreated cells.It was concluded that the subcellular translocation of ASNS may play an important role in L-asparaginase resistance in leukemia cells.