Identification of novel Cry1Ac binding proteins in midgut membranes from Heliothis virescens using proteomic analyses.

Proteins such as aminopeptidases and alkaline phosphatases, both glycosyl-phosphatidyl-inositol (GPI) anchored proteins, were previously identified as Cry1Ac binding proteins in the Heliothis virescens midgut. To identify additional toxin binding proteins, brush border membrane vesicles from H. virescens larvae were treated with phosphatidyl inositol phospholipase C, and released proteins were resolved by two-dimensional electrophoresis. Protein spots selected by their ability to bind Cry1Ac were identified by MALDI-TOF mass spectrometry coupled to peptide mass fingerprinting (PMF) and database searching. As in previous studies, H. virescens alkaline phosphatase was identified as a Cry1Ac binding protein. V-ATP synthase subunit A and actin were identified as novel Cry1Ac binding proteins in H. virescens. Additional toxin-binding proteins were predicted based on MS/MS fragmentation and de novo sequencing, providing amino acid sequences that were used in database searches to identify a phosphatase and a putative protein of the cadherin superfamily as additional Cry1Ac binding proteins.

Protein expression profiling of normal and neoplastic canine prostate and bladder tissue.

Prostatic carcinoma is an important cancer in both men and dogs. Dogs have been a valuable animal model for investigating prostate cancer, but their relevance is unclear as the origin of canine prostatic carcinomas is unknown. We hypothesized that a proteomic approach for diagnosis of these neoplasms might provide quantitative data useful for more complete characterization of their origin. Protein expression profiles were prepared from normal canine prostate glands and bladders. The normal protein profiles were then compared with protein expression profiles of three canine prostatic carcinomas. Two-dimensional differential in-gel electrophoresis (2-D DIGE) was used to analyse an average of approximately 1000 proteins per carcinoma. When compared with normal prostate tissue, the carcinomas exhibited greater than 2.5-fold difference in expression for an average of 230 proteins. Similar proteomic comparisons between the carcinomas and the normal bladder revealed a greater than 2.5-fold difference in expression for an average of 208 proteins. Mass spectrometry and protein database homology were used to identify nine proteins (alpha-enolase, vimentin, GRP78, endoplasmin (GRP94), albumin, keratins 7 and 8, haptoglobin, and transferrin) overexpressed by the carcinomas. Statistical testing demonstrated that keratin 7, GRP78, and endoplasmin were significantly overexpressed in the carcinomas compared with normal prostate or bladder. Principal components analysis revealed that the carcinomas formed a unique cluster distinct from either the normal prostate or normal bladder. In conclusion, proteomic analysis revealed that whereas the majority of proteins expressed by canine prostatic carcinomas are also expressed by normal and neoplastic bladder and prostate tissue, the carcinomas contained unique protein components that allowed their segregation as a distinct group separate from normal canine prostate and bladder. Additionally, several proteins uniquely expressed by canine prostatic carcinomas were also identified.

Secreted proteins and genes in fetal and neonatal pig adipose tissue and stromal-vascular cells.

Although microarray and proteomic studies have indicated the expression of unique and unexpected genes and their products in human and rodent adipose tissue, similar studies of meat animal adipose tissue have not been reported. Thus, total RNA was isolated from stromal-vascular (S-V) cell cultures (n = 4; 2 arrays; 2 cultures/array) from 90-d (79% of gestation) fetuses and adipose tissue from 105-d (92% of gestation) fetuses (n = 2) and neonatal (5-d-old) pigs (n = 2). Duplicate adipose tissue microarrays (n = 4) represented RNA samples from a pig and a fetus. Dye-labeled cDNA probes were hybridized to custom microarrays (70-mer oligonucleotides) representing more than 600 pig genes involved in growth and reproduction. Microarray studies showed significant expression of 40 genes encoding for known adipose tissue secreted proteins in fetal S-V cell cultures and adipose tissue. Expression of 10 genes encoding secreted proteins not known to be expressed by adipose tissue was also observed in neonatal adipose tissue and fetal S-V cell cultures. Additionally, the agouti gene was detected by reverse transcription-PCR in pig S-V cultures and adipose tissue. Proteomic analysis of adipose tissue and fetal and young pig S-V cell culture-conditioned media identified multiple secreted proteins including heparin-like epidermal growth factor-like growth factor and several apolipoproteins. Another adipose tissue secreted protein, plasminogen activator inhibitor-1, was identified by ELISA in S-V cell culture media. A group of 20 adipose tissue secreted proteins were detected or identified using the gene microarray and the proteomic and protein assay approaches including apolipoprotein-A1, apolipoprotein-E, relaxin, brain-derived neurotrophic factor, and IGF binding protein-5. These studies demonstrate, for the first time, the expression of several major secreted proteins in pig adipose tissue that may influence local and central metabolism and growth.