RNA stability regulates human T cell leukemia virus type 1 gene expression in chronically-infected CD4 T cells.

Regulation of expression of HTLV-1 gene products from integrated proviruses plays an important role in HTLV-1-associated disease pathogenesis. Previous studies have shown that T cell receptor (TCR)- and phorbol ester (PMA) stimulation of chronically infected CD4 T cells increases the expression of integrated HTLV-1 proviruses in latently infected cells, however the mechanism remains unknown. Analysis of HTLV-1 RNA and protein species following PMA treatment of the latently HTLV-1-infected, FS and SP T cell lines demonstrated rapid induction of tax/rex mRNA. This rapid increase in tax/rex mRNA was associated with markedly enhanced tax/rex mRNA stability while the stability of unspliced or singly spliced HTLV-1 RNAs did not increase. Tax/rex mRNA in the HTLV-1 constitutively expressing cell lines exhibited high basal stability even without PMA treatment. Our data support a model whereby T cell activation leads to increased HTLV-1 gene expression at least in part through increased tax/rex mRNA stability.

Understanding control in adolescent and young adult relationships.

OBJECTIVES: To describe the receipt of controlling behaviors in young women's dating relationships and the association with physical and sexual relationship violence (RV) and to ascertain whether young women experiencing controlling from partners support RV screening and respond honestly. DESIGN: Anonymous audio computer-assisted self-interview. SETTING: Reproductive health center. PARTICIPANTS: A total of 603 women aged 15 to 24 years seeking reproductive care. MAIN OUTCOME MEASURES: Self-reported victimization (controlling behaviors and physical and sexual aggression) by a partner in the past year. RESULTS: Sixty-eight percent of participants reported receiving 1 or more episodes of controlling behavior by a partner: 38.1% reported experiencing only controlling behaviors; 11.4% and 10.0% reported receiving controlling behaviors plus physical or sexual victimization, respectively; and 8.6% reported all forms of RV. Adjusted Poisson regression found that age 15 to 18 years (relative risk, 1.40), Hispanic ethnicity (1.29), childhood exposure to domestic violence (1.11), ever pregnant (1.21), older partner (1.28), recent physical (1.89) or sexual (1.93) victimization, and uncomfortable asking for condom use (1.39) were significantly associated with increased episodes of controlling behavior by a partner. Younger women and those who reported being victimized by controlling behaviors were more than twice as likely to object to screening by a health care provider, and those who reported receiving these behaviors were 2.5 times more likely to report that they might not honestly disclose RV. CONCLUSIONS: Controlling behaviors are strongly associated with physical and sexual RV. Young women experiencing controlling behaviors are more reticent about screening for RV and may not feel that they can answer honestly.

Display of somatostatin-related peptides in the complementarity determining regions of an antibody light chain.

Peptide display in antibody complementarity determining regions (CDRs) offers several advantages over other peptide display systems including the potential to graft heterologous peptide sequences into multiple positions in the same backbone molecule. Despite the presence of six CDRs in an antibody variable domain, the majority of insertions reported have been made in heavy chain CDR3 (h-CDR3) which may be explained in part by the highly variable length and sequence diversity found in h-CDR3 in native antibodies. The ability to graft peptide sequences into CDRs is restricted by amino acids in these loops that make structural contacts to framework regions or are oriented towards the hydrophobic interior and are important for the proper folding of the antibody. To identify such positions in human kappa-light chain CDR1 (kappa-CDR1) and CDR2 (kappa-CDR2), we performed alignments of 1330 kappa-light chain variable region amino acid sequences and 19 variable region X-ray crystal structures. From analyses of these alignments, we predict insertion points where sequences can be grafted into kappa-CDR1 and kappa-CDR2 to prepare synthetic antibody molecules. We then tested these predictions by inserting somatostatin and somatostatin-related sequences into kappa-CDR1 and kappa-CDR2, and analyzing the expression and ability of the modified antibodies to bind to membranes containing somatostatin receptor 5. These results expand the repertoire of CDRs that can be used for the display of heterologous peptides in the CDRs of antibodies.

The Saccharomyces cerevisiae recombination enhancer biases recombination during interchromosomal mating-type switching but not in interchromosomal homologous recombination.

Haploid Saccharomyces can change mating type through HO-endonuclease cleavage of an expressor locus, MAT, followed by gene conversion using one of two repository loci, HML or HMR, as donor. The mating type of a cell dictates which repository locus is used as donor, with a cells using HML and alpha cells using HMR. This preference is established in part by RE, a locus on the left arm of chromosome III that activates the surrounding region, including HML, for recombination in a cells, an activity suppressed by alpha 2 protein in alpha cells. We have examined the ability of RE to stimulate different forms of interchromosomal recombination. We found that RE exerted an effect on interchromosomal mating-type switching and on intrachromosomal homologous recombination but not on interchromosomal homologous recombination. Also, even in the absence of RE, MAT alpha still influenced donor preference in interchromosomal mating-type switching, supporting a role of alpha 2 in donor preference independent of RE. These results suggest a model in which RE affects competition between productive and nonproductive recombination outcomes. In interchromosome gene conversion, RE enhances both productive and nonproductive pathways, whereas in intrachromosomal gene conversion and mating-type switching, RE enhances only the productive pathway.