乳腺导管原位癌患者钼靶摄影表现与ki-67、PR、ER、HER-2表达的相关性

目的探讨乳腺导管原位癌(DCIS)患者钼靶摄影表现与ki-67、PR、ER、HER-2表达的相关性。方法回顾性分析2010年1月~2016年1月入住三明市第二医院普外科经病理检查明确诊断为DCIS的患者82例,收集82例DCIS患者的年龄、身高、体重、是否绝经、病理资料、乳腺钼靶等资料,根据乳腺钼靶摄影有无钙化分为钙化组与非钙化组,并分析两组患者的年龄、体质指数、是否绝经、乳腺钼靶表现与DCIS患者ki-67、PR、ER、HER-2表达的相关性。结果非钙化DCIS患者ki-67阳性率为58.3%(21/36),PR阳性率为52.8%(19/36),ER阳性率为55.6%(20/36),HER-2阳性率为38.7%(14/36),钙化DCIS患者的ki-67、HER-2阳性率较非钙化患者均明显升高。随着年龄的增长,DCIS患者的ki-67阳性表达率降低,HER-2阳性表达率升高;随着BMI的增加,DCIS患者的PR、ER阳性表达率亦逐渐升高;而未绝经的DCIS患者PR、ER阳性表达率较已绝经患者均明显升高。结论乳腺钼靶摄影表现为钙化的DCIS患者ki-67高表达,其HER-2亦高表达,以上特征可在一定程度上指导临床制定个体化诊治方案。     

Oxygen partial pressure modulates 67-kDa laminin receptor expression, leading to altered activity of the green tea polyphenol, EGCG

(−)-Epigallocatechin-3-O-gallate (EGCG) exhibits anti-tumor activity mediated via the 67-kDa laminin receptor (67LR). In this study, we found that 67LR protein levels are reduced by exposure to low O₂ levels (5%), without affecting the expression of HIF-1α. We also found that EGCG-induced anti-cancer activity is abrogated under low O₂ levels (5%) in various cancer cells. Notably, treatment with the proteasome inhibitor, prevented down-regulation of 67LR and restored sensitivity to EGCG under 5% O₂. In summary, 67LR expression is highly sensitive to O₂ partial pressure, and the activity of EGCG can be regulated in cancer cells by O₂ partial pressure.     

Binding of nicotinamide adenine dinucleotide phosphate to the tetratricopeptide repeat domains at the N-terminus of p67PHOX, a subunit of the leukocyte nicotinamide adenine dinucleotide phosphate oxidase

The nicotinamide adenine dinucleotide phosphate (NADPH) binding site of the NADPH oxidase complex is believed to be located on the beta, subunit of cytochrome b558. However, our previous studies showed that p67PHOX also contains an NADPH binding site that is essential for normal oxidase activity and that p67PHOX is able to mediate a slow electron transfer from a reduced pyridine nucleotide to an artificial electron acceptor. Using both affinity labeling and fluorescence quenching, we have obtained further evidence that p67PHOX is able to bind NADPH. We have used a number of truncated forms of p67PHOX, including p67PHOX(1-243), p67PHOX(1-210), p67PHOX(1-199), and p67PHOX(244-526) (where the numbers represent the initial and final amino acids in the truncated p67PHOX) in order to localize the binding site. We found that NADPH could bind to p67PHOX(1-243), p67PHOX(1-210), and p67PHOX(1-199) but not to p67PHOX(244-526). The p67PHOX(1-199) fragment consists largely of four tetratricopeptide (TPR) domains. We showed further that Rac2-GTP gamma S and to a lesser extent Rac2-GDP beta S could modulate the binding of NADPH to p67PHOX.     

A novel nucleolar protein, NIFK, interacts with the forkhead associated domain of Ki-67 antigen in mitosis

In a previous study, we demonstrated that the forkhead associated (FHA) domain of pKi-67 interacts with the novel kinesin-like protein, Hklp2 (Sueishi, M., Takagi, M., and Yoneda, Y. (2000) J. Biol. Chem. 275, 28888-28892). In this study, we report on the identification of a putative RNA-binding protein of 293 residues as another binding partner of the FHA domain of pKi-67 (referred to as NIFK for nucleolar protein interacting with the FHA domain of pKi-67). Human NIFK (hNIFK) interacted with the FHA domain of pKi-67 (Ki-FHA) efficiently in vitro when hNIFK was derived from mitotically arrested cells. In addition, a moiety of hNIFK was co-localized with pKi-67 at the peripheral region of mitotic chromosomes. The hNIFK domain that interacts with Ki-FHA was mapped in the yeast two-hybrid system to a portion encompassed by residues 226-269. In a binding assay utilizing Xenopus egg extracts, it was found that the mitosis-specific environment and two threonine residues within this portion of hNIFK (Thr-234 and Thr-238) were crucial for the efficient interaction of hNIFK and Ki-FHA, suggesting that hNIFK interacts with Ki-FHA in a mitosis-specific and phosphorylation-dependent manner. These findings provide a new clue to our understanding of the cellular function of pKi-67.     

Effect of 67Cu and 99Mo labeled tetrathiomolybdate on the distribution of 67Cu, Cu, and 99Mo in bile fractions in sheep

The effect of intravenous administration of 67Cu and 99Mo labeled tetrathiomolybdate (TTM) on the appearance of 67Cu, stable Cu, and 99Mo in gel chromatographic fractions of bile was examined in sheep fed either 5 or 35 mg Cu kg-1 DM. Peak excretory periods of biliary 67Cu, stable Cu, and 99Mo were observed at 30 min-1.25 hr, 2-3 hr, and 11-13 hr after 67Cu and after 99Mo labeled TTM. Sephadex G-75 gel filtration of bile samples collected at 1, 3, and 12 hr after 67Cu administration revealed two major protein peaks of molecular weights of greater than 80,000 (peak I) and 7,000 (peak II) containing both 67Cu and Cu. But the ratio of 67Cu in the two peaks varied with time of bile collection. The ratio of areas of peak I:II 1 hr after 67Cu administration was approximately 0.48; at 3 hr, 0.62, and at 12 hr 1.35. Tetrathiomolybdate administration increased both 67Cu and stable Cu in bile by severalfold and induced a major shift of Cu into the higher molecular weight protein fraction. The experiments confirm the effectiveness of TTM as a "decoppering" agent. Furthermore, TTM not only promoted bile Cu excretion, but it also increased the incorporation of Cu into the macromolecular fraction. This may limit enterohepatic circulation of biliary Cu and thereby cause an overall Cu depletion and a negative Cu balance.     

Expression of p53, bcl-2 and Ki-67 in cervical intraepithelial neoplasia and invasive squamous cell carcinoma of the uterine cervix

OBJECTIVE: To assess the expression of p53, bcl-2 and Ki-67 in the progression of cervical neoplasia. STUDY DESIGN: A total of 131 cervical specimens, consisting of normal cervical epithelium (n = 43), cervical intraepithelial neoplasia (CIN) lesions (n =40) and cervical squamous cell carcinomas (SCCs) (n = 48) were examined immunohistochemically in paraffin sections for expression of p53, bcl-2 and Ki-67. RESULTS: Immunoreactivity of p53 was found in 27% of SCC cases, but it had no significant relationship with SCC staging (p = 0.791). Immunoreactivity of bcl-2 was observed in 33% of CIN 3 cases. We found a significant relationship (chi2 test: p = 0.009) between the expression of bcl-2 and CIN grading. Ki-67 index was higher in high grade CIN (HGCIN: CIN 2 and 3) and SCC lesions compared to normal cervices. Ki-67 index showed a correlation with bcl-2 protein expression (p = 0.030), but not with p53 protein expression (p = 0.239). CONCLUSION: HGCIN is an early stage to demonstrate the alteration of bcl-2 and Ki-67 expressions. Progression of neoplasia in the uterine cervix is accompanied by an increase of antiapoptotic protein, bcl-2 as well as cellular proliferation.     

Evaluation of prospective, routine application of Ki-67 immunoquantitation in early CIN for assessment of short-term progression risk

OBJECTIVE: To prospectively validate, in early cervical intraepithelial neoplasia (CIN), routine assessment of a previously developed prognostic Ki-67 immunoquantitative progression-risk model. STUDY DESIGN: Two hundred sixty-six consecutive cervical biopsies taken for an abnormal cytologic smear were routinely diagnosed by experienced pathologists as CIN. Ki-67 immunoquantitation was performed routinely by 3 technicians blinded to clinical and pathologic information. Progression of CIN 1-2 to CIN 3 in histologic follow-up biopsies was used as the intermediate end point. RESULTS: In 58 (22%) biopsies, technical shortcomings prevented Ki-67 immunoquantitation, and in 22 biopsies no follow-up was available. The routine diagnosis in the 186 remaining biopsies was CIN 1 = 24, CIN 2 = 56 and CIN 3 = 106. In 52 marker biopsies with expert review diagnosis of CIN 1-2 and adequate follow-up, histologic biopsies revealed CIN 3 in 9 (17%) cases: 9 of 34 (26%) of Ki-67 high-risk and 0 of 18 (0%) of Ki-67 low-risk lesions (log rank = 5.0, P = .03). Routine CIN grade (1 or 2) was not prognostic (P = .65). Eleven (55%) of 20 CIN 1 and 7 of 32 (22%) CIN 2 cases were Ki-67 low risk and none progressed, contrasting with 4 of 9 (44%) progressions of Ki-67 high risk CIN 1s and 5 of 25 (20%) high risk CIN 2s. Expert CIN grades were stronger prognostically than routine CIN grade, but Ki-67 was still stronger. CONCLUSION: Routine Ki-67 immunoquantitative progression prediction in CIN 1-2 is more predictive of CIN 3 in follow-up than are routine and review CIN grades.     

Treatment of cells with the angiogenic inhibitor fumagillin results in increased stability of eukaryotic initiation factor 2-associated glycoprotein, p67, and reduced phosphorylation of extracellular signal-regulated kinases

Fumagillin, an angiogenic inhibitor, binds to methionine aminopeptidase 2, which is the same as eukaryotic initiation factor 2-associated glycoprotein, p67. p67 protects eIF2alpha from phosphorylation by its kinases. To understand the importance of fumagillin binding to p67, we measured the level of p67 in mouse C2C12 myoblasts treated with fumagillin. We show that fumagillin increases the stability of p67 by decreasing its turnover rate. The increased levels of p67 result in inhibition of phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERKs 1 and 2). p67 binds to these ERKs, and the 108-480 amino acid segment is sufficient for this binding. p67's affinity to ERKs 1 and 2 also increases in fumagillin-treated myoblasts while its affinity for eIF2alpha remains unchanged. A mutant at the conserved amino acid residue D251A increases the phosphorylation of ERKs 1 and 2 without affecting the binding to p67, thus indicating the importance of this residue in the regulation of the phosphorylation of these ERKs. These results suggest that fumagillin increases the stability of p67 and its affinity to ERKs 1 and 2 and causes the inhibition of the phosphorylation of ERKs 1 and 2.     

An immunohistochemical study of the expression of cell-cycle-regulated proteins p53, cyclin D1, RB, p27, Ki67 and MSH2 in gallbladder carcinoma and its precursor lesions

Gallbladder carcinomas are rare but highly lethal neoplasms. We examined the expression of five cell-cycle-related molecules (p53, RB, cyclin D1, p27, Ki-67), and MSH2, in 46 carcinomas, 14 adenomas, 15 low-grade dysplasias, 9 intestinal metaplasias and 20 normal gallbladder epithelia. The expression of these molecules was altered in gallbladder carcinomas and adenomas. In gallbladder carcinomas we observed increased expression of p53, cyclin D1, Ki-67, and MSH2 together with decreased expression of RB and p27 protein. Aberrant expression of cyclin D1 and reduced expression of RB were noted in adenomas, and expression of cyclin D1 was elevated in low-grade dysplasias. However, there was no change in the levels of these cell-cycle molecules in metaplasia. Expression of p53, p27, Ki-67, and MSH2 was correlated with clinical stage (P<0.05) and there was also a correlation between the expression of Ki-67 and MSH-2 and patient age (P<0.05). These results suggest that altered expression of cell-cycle molecules p53, cyclin D1, RB, p27, and of MSH-2 is involved in the progression of gallbladder carcinomas.     

Immunocytochemical localization of 67 KD Ca2+ binding protein (p67) in ventricular, skeletal, and smooth muscle cells.

By using immunocytochemical techniques, we examined the localization of a 67 kDa Ca2+ binding protein (p67) and calpactin I heavy chain (p36) in ventricular myocytes, skeletal myocytes, and intestinal smooth muscle cells. Immunofluorescence microscopy revealed that the p67 was expressed in all these muscle cells, whereas anti-p36 antibody stained cells in connective tissues but failed to stain these muscle cells. Immunogold electron microscopy was carried out to examine the subcellular localization of the p67 in muscle cells. The results showed that the p67 was exclusively confined to the plasma membrane of muscle cells and the presumptive transverse tubules of the striated myocytes. Immunoblot analysis with anti-p67 antibody showed that the p67 was indeed a constitutive protein of the sarcolemma isolated from rat hearts. These results indicate that the p67 is a sarcolemma-associated Ca2+ binding protein expressed in both striated myocytes and intestinal smooth muscle cells.     

The Developmental Genetics of the Temperature-Sensitive Lethal Allele of the Suppressor of Forked, l(1)su(f)ts67g, in DROSOPHILA MELANOGASTER

A temperature-sensitive lethal allele of suppressor of forked, l(1)su(f)(ts67g) (ts67), has been discovered and characterized as follows: Flies which are hemizygous for ts67 live at 18 degrees and 25 degrees but die at 30 degrees primarily as larvae. The temperature-sensitive period for ts67 homozygotes or hemizygotes begins in second instar and ends at pupation. ts67 is lethal at 30 degrees when heterozygous with suppressor of forked (su(f)), a deficiency for suppressor of forked (su(f)(-)), and a non-conditional lethal allele of suppressor of forked (3DES). It is viable at 30 degrees when heterozygous with the wild-type allele of suppressor of forked. At 25 degrees but not at 18 degrees forked bristles are suppressed in flies of the following genotypes: f(s)ts67/Y, f(s)ts67/f(s)ts67, f(s)ts67/f(s)su(f), f(u)ts67/f(s)3DES, f(u)ts67/f(s)su(f)(-), f(u)ts67/f(s)su(f). There is some suppression of forked bristles at 25 degrees in the heterozygote, f(s)ts67/f(s)+(su(f)). The forked bristle phenotype is not suppressed at either temperature in flies of the genotypes f(u)ts67/Y, f(u)ts67/f(u)ts67/ (f(s) and f(u) indicating suppressible and unsuppressible alleles of forked). The temperature-sensitive period for suppression of forked bristles begins at pupation and extends through the period of bristle synthesis. The deficiency phenotype (bristles reduced in size or absent, wing wrinkled or blistered, eyes rough) typical of flies of the genotype f(s)su(f)/f(s)su(f)(-) at 18 degrees and 25 degrees , is exhibited by flies of the genotypes f(s)ts67/f(s)su(f)(-) at 25 degrees and f(u)ts67/f(s)su(f) at 29 degrees . An allele of lozenge (lz(1)) which can be suppressed by su(f) is suppressed at 25 degrees but not at 18 degrees in lz(1)ts67/Y males. ts67 homozygous females are fertile at 25 degrees but sterile at 30 degrees . The hypothesis is discussed that the su(f) locus codes for a ribosomal protein and that suppression and enhancement are affected by mutations at the locus by mutant ribosome-induced misreading. The possibility is presented that ts67 may be used to determine the translation time in development of any gene.     

The stability of eukaryotic initiation factor 2-associated glycoprotein, p67, increases during skeletal muscle differentiation and that inhibits the phosphorylation of extracellular signal-regulated kinases 1 and 2

Eukaryotic initiation factor 2-associated glycoprotein, p67, protects eIF2 from phosphorylation by its kinases. To understand the roles of p67 during skeletal muscle differentiation of mouse C2C12 myoblasts, we measured the level of p67 during myotube formation. We noticed that the level of p67 increases during myoblast differentiation and this increased level is controlled at the translational stage. The stability of p67 in the myotubes is due to its low turnover rate. The phosphorylation of the extracellular signal-regulated kinases (ERKs 1 and 2) is high in growth-factor-mediated cycling of C2C12 myoblasts and this phosphorylation decreases at 96 h when these myoblasts are grown in differentiation medium. At this time of differentiation, the level of p67 is higher compared to 0 h of differentiation. p67 binds to ERK2 and inhibits its activity in vitro. Taken together, these results suggest that the stability of p67 increases during myotube formation while inhibiting the phosphorylation of ERKs 1 and 2.     

Suture augmentation following ACL injury to restore the function of the ACL, MCL, and medial meniscus in the goat stifle joint

Functional tissue engineering (FTE) approaches have shown promise in healing an injured anterior cruciate ligament (ACL) of the knee. Nevertheless, additional mechanical augmentation is needed to maintain joint stability and appropriate loading of the joint while the ACL heals. The objective of this study was to quantitatively evaluate how mechanical augmentation using sutures restores the joint kinematics as well as the distribution of loading among the ACL, medial collateral ligament, and medial meniscus (MM) in response to externally applied loads. Eight goat stifle joints were tested on a robotic/universal force-moment sensor testing system under two loading conditions: (1) a 67N anterior tibial load (ATL) and (2) a 67N ATL with 100N axial compression. For each joint, four experimental conditions were tested at 30°, 60°, and 90° of flexion: the (1) intact and (2) ACL-deficient joint, as well as following (3) suture repair of the transected ACL, and (4) augmentation using sutures passed from the femur to the tibia. Under the 67N ATL, suture augmentation could restore the anterior tibial translation (ATT) to within 3mm of the intact joint (p>0.05), representing a 54-76% improvement over suture repair (p<0.05). With the additional axial compression, the ATT and in-situ forces of the sutures following suture augmentation remained 2-3 times closer to normal (p<0.05). Also, the in-situ forces in the MM were 58-73% lower (p<0.05). Thus, suture augmentation may be helpful in combination with FTE approaches for ACL healing by providing the needed initial joint stability while lowering the loads on the MM.     

Autoproteolysis of rat p67 generates several peptide fragments: the N-terminal fragment, p26, is required for the protection of eIF2alpha from phosphorylation

Eukaryotic initiation factor 2-associated glycoprotein, p67, plays important roles in the regulation of eIF2alpha phosphorylation and thus maintains cell growth and proliferation. The p67 sequence can be divided into two segments, the N-terminal segment of amino acids 1-107 (p26) and the downstream segment of amino acids 108-480 (p52). Comparison of the amino acid sequences of p67 from lower to higher organisms suggests that there is a progressive addition of several unique domains at the N-terminus of p67, and these unique domains, which are present in p26, play important roles in the modulation of eIF2alpha phosphorylation in mammalian cells. To test the hypothesis that the p26 segment is generated from p67 due to its autoproteolysis and whether p26 is required for the protection of eIF2alpha from phosphorylation, we have analyzed the time-dependent cleavage of functionally active rat recombinant p67 purified from either baculovirus-infected insect cells or transiently transfected mammalian cells. We noticed a regulated cleavage of p67 that generates several peptides along with the most stable p26 and p52 fragments. The p52 fragment has a low level of autoproteolysis activity that possibly increases the autoproteolysis of full-length p67. This activity could not be inhibited by a serine protease inhibitor, PMSF, but could be inhibited by a cocktail of protease inhibitors that includes bestatin, leupeptin, E64, AEBSF, and aprotinin. To provide evidence that the fragmentation of p67 is not due to the presence of any contaminant protease(s), we fractionated purified rat p67 with molecular sieve, anion exchange, and cation exchange chromatographic steps performed in the presence of different K+ ion concentrations. Our data show that the extent of cleavage of p67 into different fragments is higher in the presence of 0.75 M K+ ion and in samples stored at -80 degrees C. Under parallel conditions, p67's mutants, D251A and D262A, exhibited very little to no cleavage, whereas the H231E mutant exhibited extensive cleavage that generated a large amount of p26 fragment. The p26 fragment exhibited protection of eIF2alpha phosphorylation both in vivo and in vitro. Altogether, our data provide evidence that rat p67 has autoproteolytic activity that generates p26, which is required to block eIF2alpha from phosphorylation.     

A glycosylation site, 60SGTS63, of p67 is required for its ability to regulate the phosphorylation and activity of eukaryotic initiation factor 2alpha

Eukaryotic initiation factor 2- (eIF2-) associated glycoprotein p67 blocks eIF2alpha phosphorylation by kinases, and its N-terminal 1-97 amino acid segment can induce efficient translation. To investigate whether glycosylation at the serine/threonine clusters at this region is important in protein synthesis, we selected (27)TSST(30) and (60)SGTS(63) clusters for further analysis. By site-directed mutagenesis, (27)TSST(30) and (60)SGTS(63) clusters were substituted with (27)AAGA(30) and (60)AGAA(63) amino acid residues in full-length p67, and their EGFP fusions were constitutively expressed in rat tumor hepatoma cells (KRC-7). The (60)AGAA(63) mutant blocked eIF2alpha phosphorylation less than either wild-type p67 or the (27)AAGA(30) mutant. The (60)AGAA(63) mutant also showed a low level of protein synthesis rate, a lower level of glycosylation, increased turnover rate, and weaker binding to eIF2alpha. These results suggest that glycosylation within the (60)SGTS(63) sequence of p67 plays an important role in its stability and thus its regulation of protein synthesis by modulating the phosphorylation of the alpha-subunit of eIF2.     

Post-translational processing in the synthesis of egg-specific protein in the silkworm,Bombyx mori

The post-translational processing of egg-specific protein (ESP) in developing ovarian follicles of the silkworm, Bombyx mori was analyzed using in vivo and in vitro labeling systems with some radioactive precursors. The labeling with[³⁵S]methionine revealed that ESP is first synthesized as 69 kDa peptide (69K-ESP) which is then converted to 72 kDa peptide (72K-ESP) until 2 h. Some of 72K-ESP molecules were converted to 64 kDa peptide (64K-ESP) after 10h-labeling. [¹⁴C]Mannose was incorporated into 69K-ESP and 72K-ESP. In the presence of tunicamycin, labeling with [³⁵S]methionine brought about a new 67 kDa peptide (67K-ESP) by reducing the incorporation into 69K- and 72K-ESP. [³²P]Ortho-phosphate was incorporated into only 72K-ESP by a 2 h-pulse labeling. Treatment of 72K-ESP with alkaline phosphatase converted it to 69K-ESP. These results along with the available information led to the conclusion that the primary translation product is sequentially processed to 67K-ESP by signal peptide cleavage, to 69K-ESP by glycosylation, and finally to 72K-ESP by phosphorylation as the actual product in the peptide synthesis. The limited conversion of 72K-ESP to 64K-ESP is proposed to be a post-endocytotic event.     

Expression of p53, p21/waf, bcl-2, bax, Rb and Ki67 proteins in colorectal adenocarcinomas

This study investigated the combined immunoexpression of p53, p21, bcl-2, bax, Rb and Ki67 proteins in colorectal adenocarcinomas and correlated expression patterns with tumour stage and grade. Paraffin sections from 98 cases of colorectal adenocarcinomas were stained by immunohistochemistry for p53, p21, bcl-2, bax, Rb and MIB-1 (Ki67) proteins. In addition, 12 cases of colorectal adenomas and normal colorectal mucosa were studied in parallel. P53, p21, bcl-2, bax, Rb and Ki67 proteins were detected in at least 5% of tumour cells in 63/98, 72/98, 52/98, 96/98 and 98/98 adenocarcinomas, respectively. Comparative study of the normal-adenoma-carcinoma tissues revealed abrogation of the normal immunotopography in adenomas and adenocarcinomas, and considerable modifications, increase or reduction, of the expression of p53, p21, bcl-2, bax, Rb and Ki67 proteins in adenocarcinomas when compared with normal mucosa and adenomas. Statistically significant correlations were found between low bax expression and Dukes C stage of carcinomas, Ki67 expression and carcinoma grade, and Ki67 and Rb expression. P53, p21, bcl-2 and Rb immunoexpression did not correlate with tumour stage or grade. Our findings show that low bax immunoexpression is frequently related to colorectal adenocarcinomas with lymph node metastases suggesting that low levels of bax expression play a role in late stage colorectal cancer. The correlation between Ki67 and Rb expression, in view of previous data that the hyperphosphorylated inactive Rb protein is frequently increased in colorectal adenocarcinomas, suggests that Rb protein is somewhat ineffective in inhibiting the cell-cycle progression in these malignancies. Furthermore, our findings provide immunohistochemical evidence that the abrogation of the normal immunotopography and the modifications of the expression of p53, p21, bcl-2, bax, Rb and Ki67 proteins reflect important events in colorectal oncogenesis.     

Binding of the Mex67p/Mtr2p heterodimer to FXFG, GLFG, and FG repeat nucleoporins is essential for nuclear mRNA export

It is not known how Mex67p and Mtr2p, which form a heterodimer essential for mRNA export, transport mRNPs through the nuclear pore. Here, we show that the Mex67p/Mtr2p complex binds to all of the repeat types (GLFG, FXFG, and FG) found in nucleoporins. For this interaction, complex formation between Mex67p and Mtr2p has to occur. MEX67 and MTR2 also genetically interact with different types of repeat nucleoporins, such as Nup116p, Nup159p, Nsp1p, and Rip1p/Nup40p. These data suggest a model in which nuclear mRNA export requires the Mex67p/Mtr2p heterodimeric complex to directly contact several repeat nucleoporins, organized in different nuclear pore complex subcomplexes, as it carries the mRNP cargo through the nuclear pore.     

Immunohistochemical expression of the p53, mdm2, p21/Waf-1, Rb, p16, Ki67, cyclin D1, cyclin A and cyclin B1 proteins and apoptotic index in T-cell lymphomas

Fifty-seven cases of T-cell lymphomas (TCL) including 5 lymphoblastic (T-LBL) and 52 peripheral TCL (PTCL) were analyzed by immunohistochemistry for the expression of p53, mdm2, p21, Rb, cyclin D1, cyclin A, cyclin B1, and Ki67/MIB1 proteins and 39/52 PTCL were also analyzed for the expression of p16 protein and for the presence of apoptotic cells by the TUNEL method. The aim was to search for abnormal immunoprofiles of p53 and Rb growth control pathways and to determine the proliferative activity and the apoptotic index of TCL. Abnormal overexpression of p53, p21 and mdm2, in comparison to normal lymph nodes, was found in 12/57, 10/57 and 2/57 cases of TCL, respectively. Abnormal loss of Rb and p16 expression was found in 1/57 and 2/39 cases, respectively, whereas abnormal overexpression of cyclin D1 was not detected in any of the 57 cases. Our data revealed entity-related p53/p21/mdm2 phenotypes. Indeed, most nodal and cutaneous CD30+ anaplastic large cell lymphomas (ALCL) showed concomitant overexpression of p53 and p21 proteins (7/8 cases), and mdm2 was overexpressed in 2 p53-positive nodal ALCL. In contrast, overexpression of p53 was found in 3/17 cases of nodal peripheral TCL unspecified (PTCL-UC) and 2/7 non-ALCL cutaneous pleomorphic TCL. Overexpression of p21 protein was detected in 2/3 p53-positive PTCL-UC and in 1/2 p53-positive non-ALCL cutaneous pleomorphic TCL. Finally, all the remaining 25 cases of TCL did not show p53 and p21 overexpression. Overall, the p53+/p21+ phenotype in 10/57 TCL suggests wild-type p53 capable of inducing p21 expression. The highest apoptotic index (AI) was found in ALCL and a positive correlation between apoptotic index and Ki67 index (p<0.001) was detected. Ki67, cyclin A and cyclin B1 expression was found in all 57 TCL and on the basis of the combined use of these 3 variables, 3 groups of proliferative activity could be determined: a) high in ALCL and T-LBL, b) low in mycosis fungoides (MF) and gammadelta hepatosplenic TCL, and c) intermediate in the remaining TCL entities. The proliferative activity in the 12 p53 overexpressing cases was higher in comparison to the 45 p53-negative cases. Ki67 expresion in more than 25% of tumour cells showed significant correlation with p53 overexpression (p<0.001). Rb expression tended to be parallel to Ki67, cyclin A and cyclin B1 expression in all but one case of nodal PTCL-UC which displayed loss of RB expression. Interestingly, this case was p53-negative, whereas the p53-positive cases were Rb-positive. These findings suggest that different pathogenetic routes may function in some TCL, involving either the p53 or, less frequently, the Rb pathways.