Although HIV-1 (HIV) replicates poorly in non-dividing CD4 lymphocytes, resting T cells contribute to the latent reservoir. The gammac-related cytokines reverse this block to HIV infection; however, the molecular mechanisms controlling this process are not understood. We asked whether the gammac-cytokine regulated transcription factor, signal transducer and activator of transcription 5 (STAT5), activates HIV transcription. We identified three regions in the long terminal repeat (LTR) as close matches to the STAT5 consensus-binding site and show that STAT5 binds the LTR during HIV infection. Expression of Janus kinase 3 (JAK3) or STAT5 in primary human CD4 T cells activated LTR transcription, while transactivation-incompetent dominant-negative STAT5 inhibited JAK3-induced LTR activity and infection of activated HIV-producing CD4 T-cells. In addition, overexpression of STAT5 increased virus production in unstimulated primary T cells - both the number of p24+ cells and their level of p24 production - suggesting that STAT5 promotes a permissive state for HIV infection. These data may have implications for regulation of latency and therapeutic strategies for control of HIV disease.
Mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene have been associated with a number of male reproductive problems, including testis abnormalities and a reduction in germ cell quality and number. To establish at least one site of functional CFTR expression in the testis, we subjected cultured Sertoli cells to analysis of message, protein, and channel activity for CFTR. With reverse transcription-polymerase chain reaction, we obtained evidence for the presence of CFTR RNA when CFTR primers were used with RNA from cultured Sertoli cells. Western analysis performed with both anti-R and anti-C domain CFTR antibodies revealed immunoreactive material in extracts from primary Sertoli cell cultures that seemed consistent with CFTR previously identified in other cells and tissues. This led us to perform more detailed studies using the whole cell arrangement of the patch-clamp technique. Application of the membrane-soluble cAMP analog, 8-chlorophenylthio-cAMP, resulted in the activation of a Cl− current that displayed a permeability sequence of Br− > I− ≥ Cl− and was blocked by diphenylamine-2-carboxylate and glibenclamide. In addition, a 13-pS conductance Cl− channel was measured in excised membrane patches exposed to the catalytic subunit of protein kinase A. When taken together, our findings of evidence of CFTR message, immunoreactive material that appeared consistent with CFTR, and Cl− channels with properties similar to those reported for CFTR provide strong evidence that Sertoli cells express a functional CFTR-like protein. The presence of CFTR in these cells may be needed to maintain the specific nutritional and fluid balance in the seminiferous tubule that is vital for normal spermatogenesis.
The cDNA for the full-length porcine estrogen receptor beta (ER beta) and an alternatively spliced transcript with a deletion of exon 5 (ER beta delta 5) was cloned from pig ovary. RNase protection assays revealed that ER beta mRNA was expressed in the preovulatory follicles and early, midluteal, and regressing corpora lutea (CL) of eCG +/- hCG-primed gilts. ER beta and ER beta delta 5 transcripts were shown by semiquantitative reverse transcription polymerase chain reaction to be expressed at a ratio of approximately 2:1 in granulosa cells, small, medium, and large antral follicles, and midluteal phase corpora lutea of unprimed animals. Immunoreactive ER beta proteins corresponding to the size of in vitro translated ER beta and ER beta delta 5 were detected by immunoblot. Full-length ER beta was detected in granulosa, small, medium, and large antral follicles, and midluteal phase CL of unprimed animals. Putative ER beta delta 5 immunoreactive bands were abundant only in granulosa cell extracts. In COS-1 cells, transfected ER beta delta 5 had no effect on basal transcription of an estrogen-responsive reporter construct but did repress wild-type ER beta transactivation when cotransfected at 10-fold excess plasmid. No repression of ER alpha transactivation was observed. In primary granulosa cell cultures, transfected ER beta delta 5 plasmid did not inhibit basal reporter activation. ER beta delta 5 was shown by immunofluorescence to localize to the nucleus in transfected COS-1 cells. In vitro translated ER beta delta 5 proteins bound estrogen response elements in DNA in electrophoretic mobility shift assays, as indicated by supershift analysis. ER beta is abundant in porcine ovary, and a naturally occurring splice variant missing exon 5 may have biological function.
The encounter of developing B cells in the bone marrow with soluble hen egg lysozyme (sHEL) self antigen induces anergy and endogenous ‹ light chain rearrangements ('receptor editing'). We have previously shown that induction of chronic graft-versus-hostreaction (GVH) in tolerant Ig/sHEL mice results in prevention of B cell anergy in the bone marrow and the spleen. We now report that in chronic GVH, immature self-reactive B cells also show reduced levels of receptor editing in the bone marrow. This is evidenced by the following observations: (a) a small population of 'receptor-edited' B cells, which is found in tolerant mice, is markedly reduced in mice that have lost tolerance in chronic GVH; (b) self-reactive B cells in GVH mice have reduced levels of endogenous ‹ chain rearrangements; and (c) recombinase-activating gene (RAG)-2 expression is markedly decreased in immature selfreactive B cells in the bone marrow of chronic GVH mice. These results suggest that in chronic GVH newly emerging B cells escape tolerance, in part because of decreased receptor editing in the bone marrow. Thus, the autoimmunity induced by chronic GVH may ultimately result from the failure of B cell tolerance at multiple checkpoints.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.