Conservative mutations in the putative metal-binding region of human immunodeficiency virus tat disrupt virus replication.

The tat trans-activator proteins of the primate immunodeficiency viruses contain a highly conserved cysteine-rich domain. In human immunodeficiency virus type 1 tat there are seven cysteines located between residues 22 and 37 that are thought to form a metal-nucleic acid-binding structure. Most of the previous mutagenesis studies had demonstrated that these residues are essential for tat activity and virus expression.

Human immunodeficiency virus type 1 rev protein as a negative trans-regulator.

Even though the rev gene of the human immunodeficiency virus type 1 (HIV-1) is essential for viral replication, high levels of rev also downregulate viral gene expression. As the degree of rev protein expression exceeds expression of wild-type virus, a gradient of decreasing viral mRNA synthesis becomes evident. The target sequence for this downregulation resides outside of trans-activating region (TAR) and upstream from the enhancer sequences in the long terminal repeat (LTR), suggesting that regulation is at a transcriptional level.

[IgM multiple myeloma (author's transl)].

A new case of IgM myeloma in a 47-year-old man is reported. Multiple myeloma was diagnosed by serum electrophoresis and immunoelectrophoresis, marrow plasmocytosis and typical skeletal changes by X - Ray the synthesis of the M - component was demonstrated in the plasma cells of the bone marrow by direct immunofluorescence study. A review of literature was done and relation between macroglobulinemia of Waldenström and IgM myeloma was discussed.