Acute appendicitis is characterized by a uniform and highly selective pattern of inflammatory gene expression.

Acute appendicitis (AA) is the most common life-threatening surgical emergency in pediatrics. To characterize the nature of the inflammatory response in AA, gene expression profiles were generated. We found remarkable uniformity in the genes that were differentially expressed between patients with appendicitis and control groups. Sixty-four probe sets were differentially expressed in samples from patients with both severe and mild appendicitis compared to control samples, and within this group we were able to identify four dominant clusters. Interestingly, expression levels of interleukin (IL)-8 significantly correlated with histologic score, and expression of IL-8 protein was observed within both neutrophils and mononuclear cells by immunohistochemistry, suggesting a possible role in the etiology of appendicitis. Although there was some overlap between genes reported to be differentially expressed in Crohn's disease (CD) and those observed in AA, differential expression of genes involved in interferon responses that characterize CD was not observed.

Editing of hnRNP K protein mRNA in colorectal adenocarcinoma and surrounding mucosa.

The heterogeneous nuclear ribonucleoprotein K (hnRNP K) protein is an RNA-binding protein involved in many processes that compose gene expression. K protein is upregulated in the malignant processes and has been shown to modulate the expression of genes involved in mitogenic responses and tumorigenesis. To explore the possibility that there are alternative isoforms of K protein expressed in colon cancer, we amplified and sequenced K protein mRNA that was isolated from colorectal cancers as well as from normal tissues surrounding the tumours. Sequencing revealed a single G-to-A base substitution at position 274 that was found in tumours and surrounding mucosa, but not in individuals that had no colorectal tumour. This substitution most likely reflects an RNA editing event because it was not found in the corresponding genomic DNAs. Sequencing of RNA from normal colonic mucosa of patients with prior resection of colorectal cancer revealed only the wild-type K protein transcript, indicating that G274A isoform is tumour related. To our knowledge, this is the first example of an RNA editing event in cancer and its surrounding tissue, a finding that may offer a new diagnostic and treatment marker.

Specificity-determining regions of a lepidopteran-specific insecticidal protein produced by Bacillus thuringiensis.

The lepidopteran-specific, insecticidal crystal proteins of Bacillus thuringiensis vary in toxicity to different species of lepidopteran larvae. We report studies of CryIA(a) and CryIA(c), two related proteins that have different degrees of toxicity to Heliothis virescens yet very similar degrees of toxicity to Manduca sexta. The amino acid differences between these proteins are located primarily between residues 280 and 722. We have constructed a series of chimeric proteins and determined their toxicities to both insects. The most significant findings arise from the replacement of three segments of the cryIA(c) gene with homologous portions of the cryIA(a) gene: codons 332-428, 429-447, and 448-722. Each of these segments contributed substantially and largely additively toward efficacy for H. virescens. However, replacement of the 429-447 segment of cryIA(c) gene with the cryIA(a) sequence resulted in a 27-50-fold reduction in toxicity toward M. sexta whereas the reduction in toxicity to H. virescens was only 3-4-fold. Subdivision of the 429-447 segment and replacements involving residues within this segment reduced toxicity to M. sexta by 5- to more than 2000-fold whereas toxicity to H. virescens was only reduced 3-10-fold. These observations indicate that: 1) different but overlapping regions of the cryIA(c) gene determine specificity to each of the two test insects; 2) some of the examined gene segments interact in determining specificity; and 3) different sequences in the cryIA(a) and cryIA(c) genes are required for maximal toxicity to M. sexta.

Hyperdegradation of proteins in Escherichia coli rho mutants.

An Escherichia coli mutant, HDF026, defective for growth of phage T4, has been characterized biochemically and genetically. The mutant displays an elevated level of degradation of abnormal proteins, such as puromycyl polypeptides or canavanine-containing polypeptides. Genetically, HDF026 appears to be an allele of rho, which also encodes the transcription termination factor and RNA-dependent ATPase, Rho. The mutation contransduces by phage PI with ilv, weakly suppresses polar mutations in gal, and permits some growth of lambda N- phage. Temperature sensitive lambda mutants in gene O exhibit a reduced efficiency of plating at intermediate temperature on HDF026 mutants; presumably the lambda Ots protein is rapidly degraded in these strains. The ability of wild-type lambda to grow on HDF026 is also reduced, apparently the result of the lambda N product deficiency. gal escape synthesis, which reflects the level of lambda N activity, is decreased 50-66% in the HDF026 mutant. lambda r32, which requires more N function than wild-type phage, does not grow at all in HDF026. A lon mutation, which decreases protein degradation, partially reverses some of these phenotypes, suggesting that they are related to the protein hyperlability of HDF026.

Bacteriophages inhibit degradation of abnormal proteins in E. coli.

On infection of Escherichia coli cells by bacteriophages T4, T5 or T7, the degradation of E. coli protein fragments and abnormal proteins is inhibited. Normal E. coli proteins, however, continue to be degraded at their usual rates. T4 early proteins (s) is needed to inhibit the turnover of abnormal proteins in T4-infected E. coli cells.