Screening Molecular Chaperones Similar to Small Heat Shock Proteins in Schizosaccharomyces pombe

To screen molecular chaperones similar to small heat shock proteins (sHsps), but without alpha-crystalline domain, heat-stable proteins from Schizosaccharomyces pombe were analyzed by 2-dimensional electrophoresis and matrix assisted laser desorption/ionization time-of-flight mass spectrometry. Sixteen proteins were identified, and four recombinant proteins, including cofilin, NTF2, pyridoxin biosynthesis protein (Snz1) and Wos2 that has an alpha-crystalline domain, were purified. Among these proteins, only Snz1 showed the anti-aggregation activity against thermal denaturation of citrate synthase. However, pre-heating of NTF2 and Wos2 at 70degrees C for 30 min, efficiently prevented thermal aggregation of citrate synthase. These results indicate that Snz1 and NTF2 possess molecular chaperone activity similar to sHsps, even though there is no alpha-crystalline domain in their sequences.

Alpha basic crystallin expression in canine mammary tumors

The aim of this study was to evaluate prognostic and/or diagnostic factors of canine mammary tumors by immunohistochemically analyzing the expression of alpha basic crystallin (alphaB-c). For this, formalin-fixed, paraffin-embedded blocks of 51 naturally-occurring canine mammary tumors (11 benign and 40 malignant) were used. Tissue from eight normal canine mammary glands were served as a control. Immunohistochemically, in the control mammary tissues, a few luminal epithelial cells were alphaB-c positive but myoepithelial cells were negative. In benign or simple type malignant tumors, alphaB-c expression was observed in luminal epithelial cells while the myoepithelial basal cells were negative. In benign or complex type malign tumors, positive staining was predominantly found in the cytoplasm of epithelial cells. Immunoreactivity of alphaB-c was also observed in neoplastic myoepithelial cells. Statistically, the number of cells immunolabeled with alphaB-c was found to be significantly different among tissues from normal canine mammary glands, benign lesions, and malignant tumors (p < 0.05). alphaB-c immunoreactivity was higher in malignant tumors than the control mammary tissues (p < 0.001). Data obtained in the current study revealed a strong association between high expression levels of alphaB-c and primary mammary gland tumors in canines.

Lens proteome map and -crystallin profile of the catfish Rita rita.

Crystallins are a diverse group of proteins that constitute nearly 90% of the total soluble proteins of the vertebrate eye lens and these tightly packed crystallins are responsible for transparency of the lens. These proteins have been studied in different model and non-model species for understanding the modifications they undergo with ageing that lead to cataract, a disease of protein aggregation. In the present investigation, we studied the lens crystallin profile of the tropical freshwater catfish Rita rita. Profiles of lens crystallins were analyzed and crystallin proteome maps of Rita rita were generated for the first time. A-crystallins, member of the -crystallin family, which are molecular chaperons and play crucial role in maintaining lens transparency were identified by 1-and 2-D immunoblot analysis with anti-A-crystallin antibody. Two protein bands of 19-20 kDa were identified as A-crystallins on 1-D immunoblots and these bands separated into 10 discrete spots on 2-D immunoblot. However, anti-B-crystallin and antiphospho-B-crystallin antibodies were not able to detect any immunoreactive bands on 1- and 2-D immunoblots, indicating B-crystallin was either absent or present in extremely low concentration in Rita rita lens. Thus, Rita rita -crystallins are more like that of the catfish Clarias batrachus and the mammal kangaroo in its A- and B-crystallin content (contain low amount from 5-9% of aB-crystallin) and unlike the dogfish, zebrafish, human, bovine and mouse -crystallins (contain higher amount of B-crystallin from 25% in mouse and bovine to 85% in dogfish). Results of the present study can be the baseline information for stimulating further investigation on Rita rita lens crystallins for comparative lens proteomics. Comparing and contrasting the -crystallins of the dogfish and Rita rita may provide valuable information on the functional attributes of A- and B-isoforms, as they are at the two extremes in terms of A-and B-crystallin content.

Distal hereditary motor neuropathy in Korean patients with a small heat shock protein 27 mutation

Distal hereditary motor neuropathy (dHMN) is a heterogeneous disorder characterized by degeneration of motor nerves in the absence of sensory abnormalities. Recently, mutations in the small heat shock protein 27 (HSP27) gene were found to cause dHMN type II or Charcot-Marie-Tooth disease type 2F (CMT2F). The authors studied 151 Korean axonal CMT or dHMN families, and found a large Korean dHMN type II family with the Ser135Phe mutation in HSP27. This mutation was inherited in an autosomal dominant manner, and was well associated with familial members with the dHMN phenotype. This mutation site is located in the ?-crystallin domain and is highly conserved between different species. The frequency of this HSP27 mutation in Koreans was 0.6%. Magnetic resonance imaging analysis revealed that fatty infiltrations tended to progressively extend distal to proximal muscles in lower extremities. In addition, fatty infiltrations in thigh muscles progressed to affect posterior and anterior compartments but to lesser extents in medial compartment, which differs from CMT1A patients presenting with severe involvements of posterior and medial compartments but less involvement of anterior compartment. The authors describe the clinical and neuroimaging findings of the first Korean dHMN patients with the HSP27 Ser135Phe mutation. To our knowledge, this is the first report of the neuroimaging findings of dHMN type II.

Regulation of alpha-crystallin gene expression by glucocorticoids in lens epithelial cells

PURPOSE: The purpose of this study was to examine the molecular basis for steroid-induced cataract and the specific aim was to investigate the potential effects of glucocorticoids on modulation of alpha-crystallin gene expression in lens epithelial cells. METHOD: Bovine lens epithelial explants, B-3 human lens epithelial cells, and alphaTN4 mouse lens epithelial cells were incubated in the absence or presence of dexamethasone. At the indicated time point, total cellular RNA was isolated and subjected to RT-PCR and Northern blot analysis to assess mRNA expression of alphaA- and alphaB-crystallin. RESULTS: The mRNA expression of alphaA-crystallin was drastically downregulated by treatment with dexamethasone in bovine, human, and mouse lens epithelial cells. The mRNA level of alphaA-crystallin was also decreased in response to hydrocortisone but not to estrogen. The stability of the alphaA-crystallin mRNA was decreased after dexamethasone treatment. CONCLUSIONS: These results suggest that the alteration of alphaA-crystallin gene expression by glucocorticoids may result in abnomal structure and differentiation of lens epithelial cells on steroid-induced cataract formation.