The Rex locus of Drosophila melanogaster induces a high frequency of mitotic exchange between two separated ribosomal DNA arrays on a single chromosome. The exchanges take place in the progeny of Rex mothers and occur very early, before the third mitotic division. A number of common laboratory stocks have also been found to carry dominant suppressors of Rex (Su(Rex)). Rex was mapped to the X ce...

The Rex trans-regulatory protein of human T-cell leukemia virus type 1 (HTLV-1) is required for the nuclear export of incompletely spliced and unspliced viral mRNAs and is therefore essential for virus replication. Rex is a nuclear phosphoprotein that directly binds to its cis-acting Rex response element RNA target sequence and constantly shuttles between the nucleus and cytoplasm. Moreover, Re...

The regulatory role of redox-sensing regulator Rex was investigated in Streptomyces avermitilis. Eleven genes/operons were demonstrated to be directly regulated by Rex; these genes/operons are involved in aerobic metabolism, morphological differentiation, and secondary metabolism. Rex represses transcription of target genes/operons by binding to Rex operator (ROP) sequences in the promoter regi...

Human T-cell leukemia virus (HTLV) regulatory protein, Rex, functions to increase the expression of the viral structural and enzymatic gene products. The phosphorylation of two serine residues (S151 and S153) at the C terminus is important for the function of HTLV-2 Rex (Rex-2). The Rex-2 phosphomimetic double mutant (S151D, S153D) is locked in a functionally active conformation. Since rex and ...

Rex-1 (Zfp-42) is a known marker for undifferentiated embryonic stem cells and teratocarcinoma cells. However, the mechanism by which Rex-1 is regulated in pluripotent cells remains unresolved. Here we report that Nanog, an Nk-2 homeodomain protein known for its role in maintaining stem cell pluripotency, is a transcription activator for the Rex-1 promoter. Knockdown of Nanog in embryonic stem ...

on expression of the Xrex+ gene, since little inhibition was observed following infection by a Xrex mutant or by a hybrid bacteriophage Xii44 which lacks a functional rex gene. For promotion of the synthesis of rex product, cII+ and N+ genes are required and can act trans, whereas cY+, also required, must be cis to a rex+ gene. These genes presumably play a role in the transcription of the cd-r...

Human T-cell leukemia virus type 1 (HTLV-1) is a complex retrovirus associated with the lymphoproliferative disease adult T-cell leukemia/lymphoma (ATL) and the neurodegenerative disorder tropical spastic paraparesis/HTLV-1-associated myelopathy (TSP/HAM). Replication of HTLV-1 is under the control of two major trans-acting proteins, Tax and Rex. Previous studies suggested that Tax activates tr...

Rex, a transcriptional repressor that modulates its DNA-binding activity in response to NADH/NAD(+) ratio, has recently been found to play a role in the solventogenic shift of Clostridium acetobutylicum. Here, we combined a comparative genomic reconstruction of Rex regulons in 11 diverse clostridial species with detailed experimental characterization of Rex-mediated regulation in C. acetobutyli...

Human T-cell leukemia virus type-1 (HTLV-1) Rex is a viral RNA binding protein. The most important and well-known function of Rex is stabilizing and exporting viral mRNAs from the nucleus, particularly for unspliced/partially-spliced mRNAs encoding the structural proteins essential for viral replication. Without Rex, these unspliced viral mRNAs would otherwise be completely spliced. Therefore, ...

The posttranscriptional regulator (rex) of human T-cell leukemia virus type I is known to be located predominantly in the cell nucleolus and to induce the accumulation of gag and env viral mRNAs. The N-terminal 19 amino acids of rex-encoded protein (Rex) has been shown to be sufficient to direct hybrid proteins to the cell nucleolus. We have studied the function of the nucleolar targeting signa...