Expression and function of TRAF-3 splice-variant isoforms in human lymphoma cell lines

TRAF-3 gene products are signaling adaptor molecules required for lymphocytes to mediate T-dependent antibody responses in vivo. Previous work identified 8 splice-variant TRAF-3 mRNA species by RT-PCR that have the potential to encode novel isoforms, seven of which induce NF-kappaB activation when over-expressed in 293 cells. Here, their expression was characterized by RNAse protection assay, which showed the T cell line Jurkat D1.1 and the B cell lines BJAB, Daudi, and Raji each expressed mRNA encoding TRAF-3 splice-variants in approximately the same rank order (from highest to lowest); TRAF-3 Delta103aa, Delta83aa, full-length, Delta25aa, Delta52aa, Delta56aa, Delta27aa, and Delta221aa mRNA. The TRAF-3 Delta130aa mRNA was not detectable in any of the cell lines examined. The functional effect of over-expressing each TRAF-3 splice-variant on NF-kappaB activation was studied in the TRAF-5-responsive B cell line, BJAB. Of the seven TRAF-3 splice-variant isoforms that induce NF-kappaB activation in 293 cells, only TRAF-3 Delta27aa, Delta103aa, or Delta130aa induce NF-kappaB activation in BJAB cells. Together, these data indicate that a number of TRAF-3 splice-variant mRNAs are expressed and function in B and T lymphoma lines, which suggests that certain TRAF-3 splice-variant isoforms may participate in mediating the known functions of the TRAF-3 gene in lymphocytes.

TRAF-3 interacts with p62 nucleoporin, a component of the nuclear pore central plug that binds classical NLS-containing import complexes

The TRAF-3 gene encodes a number of splice-variant isoforms that function as adapter molecules in NF-kappaB signaling, in part by associating with the cytoplasmic tails of CD40 or other TNF-receptor (TNF-R) family members. To identify downstream molecules in TRAF-3 signaling, a yeast two-hybrid library was screened with a full-length TRAF-3 construct. Nine independent TRAF-3 interacting clones encoded fragments of p62 Nucleoporin (p62), a 522 amino acid (aa) component of the nuclear pore central plug, that is known to bind karyopherin-beta/classical-NLS import factor complexes. The interaction of p62 with TRAF-3 was specific, since p62 failed to interact with TRAF-2, -4, -5, or -6. Deletional analysis in yeast revealed that the p62:TRAF-3 interaction is mediated by a p62 carboxy (C)-terminal coiled-coil domain and TRAF-3's fifth zinc (Zn) finger and coiled-coil domain. In human 293 T cells, recombinant TRAF-3 or p62 specifically co-immunoprecipitates the other species. In addition, endogenous p62 co-precipitates over-expressed TRAF-3. The functional effects of over-expressing a TRAF-3 binding fragment, p62(aa 336-522) were studied on NF-kappaB-dependent, or control STAT1-dependent reporter activity in 293 T cells, either resting or after stimulation by CD40 or IFN-gamma, respectively. Over-expression of p62(aa 336-522) induces NF-kappaB activation in resting cells and augments CD40-induced NF-kappaB activation, but has no effect on control STAT1 reporter activity, either at baseline or after IFN-gamma induction. The finding that TRAF-3 binds p62, suggests that TRAF-3 may serve as an adapter molecule at the nuclear membrane, in addition to its known adapter function at the plasma membrane.

Unsuspected primary tubal carcinoma during operative laparoscopy

OBJECTIVE

To evaluate the possible risk of dealing with an unsuspected primary carcinoma of the fallopian tube during laparoscopic surgery.

METHODS

We performed a countrywide survey in Austria concerning laparoscopic procedures in cases of primary carcinoma of the tube. The questionnaire consisted of questions regarding the pre-, intra-, and postoperative management.

RESULTS

Of 18,435 laparoscopies in cases of an adnexal mass, 5 cases were reported, when laparoscopy was performed on an unsuspected carcinoma of the tube. Therefore, the risk of detecting this malignancy during laparoscopy after preoperative evaluation is 1 in 3687 cases (0.028%).

CONCLUSION

The risk of encountering an unsuspected primary carcinoma of the fallopian tube during laparoscopy in Austria is an extremely rare situation. In case of a malignancy, a staging or debulking laparotomy should be performed immediately or as soon as possible.

A Clarkson's sector integration routine for personal computers

A Clarkson's sector integration scheme has been implemented on a personal computer to calculate mean scatter-air ratio (SAR) and mean tissue-air ratio (TAR) for external photon beams of irregular shape. To find where a given radial line from the point of interest intersects the edge of the radiation field, polygon clipping algorithms have been adapted from the field of image processing. The program has calculation run times of approximately 1 s on an 80387 with a math coprocessor for an integration of 36 sectors. The software was validated by comparison to program IRREG, where for various squares and clinical shapes, the agreement was typically 0.7%. The source code is available from the authors.