Characterization of size-fractionated cDNA libraries generated by the in vitro recombination-assisted method.

We here modified a previously reported method for the construction of cDNA libraries by employing an in vitro recombination reaction to make it more suitable for comprehensive cDNA analysis. For the evaluation of the modified method, sets of size-selected cDNA libraries of four different mouse tissues and human brain were constructed and characterized. Clustering analysis of the 3' end sequence data of the mouse cDNA libraries indicated that each of the size-fractionated libraries was complex enough for comprehensive cDNA analysis and that the occurrence rates of unidentified cDNAs varied considerably depending on their size and on the tissue source. In addition, the end sequence data of human brain cDNAs thus generated showed that this method decreased the occurrence rates of chimeric clones by more than fivefold compared to conventional ligation-assisted methods when the cDNAs were larger than 5 kb. To further evaluate this method, we entirely sequenced 13 human unidentified cDNAs, named KIAA1990-KIAA2002, and characterized them in terms of the predicted protein sequences and their expression profiles. Taking all these results together, we here conclude that this new method for the construction of size-fractionated cDNA libraries makes it possible to analyze cDNAs efficiently and comprehensively.

Kinetic profiles of sequential gene expressions for chemokines in mice with contact hypersensitivity.

Using cDNA microarray technology, the expression of chemokine genes in the elicitation site of 2,4,6-trinitrochlorobenzene-induced contact hypersensitivity (CHS) was examined in mice. Of the 33 genes analyzed, levels of 11 gene expressions changed, and these can be assigned to four groups based on their kinetic patterns; (1) LARC/CCL20 whose mRNA level increased rapidly at 3 h post-challenge and then gradually decreased, (2) JE/CCL2, MARC/CCL7, MIP-1gamma/CCL9, monocyte chemoattractant protein (MCP)-5/CCL12, ELC/CCL19 and BRAK/CXCL14 whose mRNA levels increased with time and reached the maximum at 6-9 h post-challenge, (3) LIX/CXCL5, Mig/CXCL9 and IP-10/CXCL10 whose mRNA levels increased gradually at least up to 12 h post challenge, and (4) SLC/CCL21 whose mRNA level decreased gradually with time after challenge. The findings suggest that sequential expression of chemokine genes is essential for orientating non-specific skin response to hapten-specific CHS response through the recruitment of inflammatory cells such as neutrophils, monocytes/macrophages and T-cells from the circulation into the tissue site.

Effect of a topical steroid on gene expressions for chemokines in mice with contact hypersensitivity.

Effects of a topical corticosteroid drug, diflucortolone valerate, on the mRNA expressions for four CC- and four CXC-chemokines, which have been reported to be associated with recruitment of different kinds of proinflammatory and inflammatory cells, were investigated by RT-PCR in mice with 2,4,6-trinitrochlorobenzene (TNCB)-induced contact hypersensitivity (CHS) response. All of the eight gene expressions were clearly up-regulated in the lesion site of the CHS response up to 24 h post-challenge of TNCB at which ear swelling response reached a peak, so that heavy infiltration of inflammatory cells consisting mainly of mononuclear cells and neutrophils was likely induced by these chemokines. Topical treatment with diflucortolone valerate suppressed completely the infiltrates as well as the ear swelling response. In addition, the up-regulation of gene expressions for these eight chemokines were suppressed by the treatment, indicating that the corticosteroid drug attenuates the expression of chemokine genes essential for orientating nonspecific skin response to hapten-specific CHS response through the recruitment of inflammatory cells from the circulation into the tissue site.