The influence of perioperative blood transfusion on intrahepatic recurrence after curative resection of hepatocellular carcinoma

OBJECTIVE

This study retrospectively evaluated the association between perioperative blood transfusion and intrahepatic recurrence in patients with hepatocellular carcinoma (HCC) who had undergone curative hepatic resections.

METHODS

Hepatic resection was performed with curative intent in 195 patients with primary HCC between 1985 and 1996. Patients who had received perioperative blood transfusion (transfused group: n = 117) and those who had no perioperative blood transfusion (nontransfused group: n = 78) were compared in terms of conventional prognostic variables and cancer-free survival by the univariate and multivariate analyses.

RESULTS

The 1-, 3-, and 5-yr cancer-free survival rates in the nontransfused and transfused groups were 83.4% and 67.9%, 43.0% and 36.7%, and 23.1% and 24.6%, respectively (p = 0.175). Multivariate analysis of prognostic factors in all patients revealed that vascular invasion, tumor size (> or =5 cm), and Child's class were independent factors for intrahepatic recurrence. Further analyses in various stratified groups showed that perioperative blood transfusion was an independent predictor of prognosis in HCC patients with portal vein invasion (RR: 2.8, p = 0.0038). The 1-, 3-, and 5-yr survival rates in the nontransfused and transfused groups with portal vein invasion were 71.9% and 41.6%, 54.5% and 10.9%, and 26% and 0%, respectively (p = 0.0003).

CONCLUSIONS

We conclude that perioperative blood transfusions enhance the risk of intrahepatic recurrence of HCC in patients with portal vein invasion. As well, the more difficult surgery and the increased manipulation of the liver that occur in these cases create a greater possibility of tumor dissemination.

Exacerbation of renal failure due to hypothyroidism in a patient with ischemic nephropathy

A case of acute-on-chronic renal failure in a 70-year-old woman with ischemic nephropathy and primary hypothyroidism is presented. Her renal function became progressively worse as the level of serum creatinine increased from 283 to 628 micromol/l (3.2-7.1 mg/dl) within 8 months. Her thyroid function had been normal before the exacerbation of renal failure, but it was markedly reduced with a marked elevation of serum thyroid-stimulating hormone. Thyroid hormone replacement therapy resulted in rapid improvement of the renal function to 159 micromol/l (1.8 mg/dl) of serum creatinine. The development of primary hypothyroidism seemed to worsen the already impaired renal function in this case. We suggest the assessment of thyroid function in patients with unexplained deterioration of renal failure.

Two Taenia species found in Japan, with new distribution record of Taenia polyacantha Leuckart, 1856 (Cestoda: Taeniidae)

In an epidemiological survey for Echinococcus multilocularis in rodents and insectivores from the northernmost part of the central mainland of Japan (Honshu), two taeniid species, Taenia crassiceps and Taenia polyacantha, were found in Microtus montebelli and Apodemus argenteus, respectively. The latter is the first record of distribution in Japan, and the former is the second after its first recovery from the central part of Japan. Although we have found neither larval nor strobilar stage of E. multilocularis there, discovery of these taeniid species, having overlapping global distribution with E. multilocularis in red foxes Vulpes vulpes as well as multiple occurrences of hydatid patients having no history of visits to the endemic areas shows the possibility that the life-cycle of E. multilocularis might be maintained at least in the northernmost part of Honshu.

Hydrophilic residues at the apical domain of GroEL contribute to GroES binding but attenuate polypeptide binding

The GroES binding site at the apical domain of GroEL, mostly consisting of hydrophobic residues, overlaps largely with the substrate polypeptide binding site. Essential contribution of hydrophobic interaction to the binding of both GroES and polypeptide was exemplified by the mutant GroEL(L237Q) which lost the ability to bind either of them. The binding site, however, contains three hydrophilic residues, E238, T261, and N265. For GroES binding, N265 is essential since GroEL(N265A) is unable to bind GroES. E238 contributes to rapid GroES binding to GroEL because GroEL(E238A) is extremely sluggish in GroES binding. Polypeptide binding was not impaired by any mutations of E238A, T261A, and N265A. Rather, these mutants, especially GroEL(N265A), showed stronger polypeptide binding affinity than wild-type GroEL. Thus, these hydrophilic residues have a dual role; they help GroES binding on one hand but attenuate polypeptide binding on the other hand.

Risk of stroke in relation to level of blood pressure and other risk factors in treated hypertensive patients

BACKGROUND AND PURPOSE

Treatment of hypertension effectively reduces the risk of stroke. However, many treated patients still have high blood pressure (BP), other cardiovascular risk factors, and complications. The risk of stroke in treated hypertensive patients is not well understood.

METHODS

We analyzed the level of BP over 1 year before the onset of stroke and other cardiovascular risk factors in treated hypertensive patients in a case-control study. The study population included 126 hypertensive patients (74 men; mean age, 70.9 years) with first strokes during 1988-1993 who had been treated for >1 year before stroke onset (stroke group). As a control group, we selected 126 sex- and age-matched hypertensive patients who were treated during the same period and were free from stroke.

RESULTS

Mean 12-month BP was not significantly different between stroke and control groups, although systolic BP was 2.5 mm Hg higher in the stroke group (148.7 [95% CI, 146.1 to 151.3]/82.1 [95% CI, 80.5 to 83.7] versus 146.2 [95% CI, 143.8 to 148.6]/82.4 [95% CI, 81.0 to 83.8] mm Hg). In patients aged <70 years, mean systolic BP was significantly higher in the stroke group than the control group (150.5 [146.3 to 154.7] versus 144.0 (140.6 to 147.4) mm Hg). Mean pulse pressure was also significantly higher in the stroke group than the control group in patients aged <70 years but not in older patients. In the stroke group, the level of BP within 1 month before stroke onset did not differ from the mean value over the 12-month period. Patients with brain hemorrhage had higher diastolic BP than those with other subtypes. The stroke group had higher plasma glucose, lower HDL cholesterol, and higher frequencies of diabetes mellitus, proteinuria, atrial fibrillation (29.4% versus 4.0%), and use of antiplatelet (31.0% versus 11.1%) and anticoagulant (10.3% versus 1.6%) agents than the control group.

CONCLUSIONS

The onset of stroke in treated hypertensive patients was related to a higher level of BP in subjects <70 years old, although this relationship was not obvious in older patients. The risk of stroke in these patients was associated with the presence of metabolic risk factors and cardiovascular complications. Office BP did not change significantly 1 month before the onset of stroke.

Clinical results of fetal obstructive uropathy treated by vesicoamniotic shunting

OBJECTIVES

To report the clinical results of 5 fetuses after a vesicoamniotic shunting procedure (VASP).

METHODS

Between 1995 and 1998, 5 patients (two with prune belly syndrome, one with a cloacal anomaly, one with urethral stenosis, and one with a sacrococcygeal teratoma) underwent VASP using a double-basket catheter. We used the following selection criteria: a fetus without chromosomal defects, with oligohydramnios, and with a predicted good renal function from sequential or single fetal urinalysis (sodium concentration, chloride concentration, and osmolarity at less than 100 mEq/L, less than 90 mEq/L, and less than 210 mOsm, respectively).

RESULTS

The mean gestational age was 20.8 +/- 6.9 weeks at diagnosis, 24.2 +/- 6.0 weeks at VASP, and 30.6 +/- 6.2 weeks at delivery. In our study, 2 of 5 patients survived. One of the patients with prune belly syndrome was 18 months old at last follow-up, with hydrocephalus and a creatinine level of 0.2 mg/dL. The patient with the cloacal anomaly was 4 years old at last follow-up and had signs of clonic convulsion. However, psychomotor development was delayed in both. Of the 3 patients who died, 2 died after birth, and the autopsy determined death was due to pulmonary insufficiency. The patient with urethral stenosis died in utero.

CONCLUSIONS

Although the principal purpose of VASP is to prevent pulmonary hypoplasia and dysfunctional kidneys, VASP was not always effective, as the outcomes were poor in most of our patients. A greater standardization of patient selection and a large cohort study in the future should be considered to assess VASP.

Induced expression, localization, and chromosome mapping of a gene for the TBP-interacting protein 120A

TBP-interacting protein 120A (TIP120A) is a novel eukaryotic transcriptional regulator and has been suggested to be involved in the general regulation of transcription because of its ability to potentiate transcription of all classes of genes and to interact with common transcriptional machineries. In the present study, we investigated the expression of the tip120a gene. TIP120A transcripts were expressed abundantly in the heart and liver, moderately in the brain and skeletal muscle, and only slightly in the spleen and lung. This ubiquitous expression pattern was similar to that of TBP. Gene expression of TIP120A in the rat liver was not stimulated by hepatocarcinogenesis or liver regeneration. TIP120A was thus suggested not to be a growth-related protein. On the other hand, in P19 mouse embryonal carcinoma cells, TIP120A expression was elevated upon retinoic acid treatment, which induces differentiation. Notably, the foci-like nuclear localization pattern of TIP120A was transformed into a speckle-like pattern. The level of TIP120A was also elevated in such stem-like cells as F9 and HL60 after each differentiation procedure, retinoic acid and DMSO, respectively. In HEp-2 cells, TIP120A was observed as a limited number of nuclear foci, and the localization coincided with that of the PML oncogenic domain. FISH detection revealed that the human tip120a gene was located at 12q14, the position to which a myopathic type scapuloperoneal syndrome locus also mapped. Our study suggests that, contrary to an early assumption, TIP120A is involved in tissue-specific and/or differentiation-related gene expression.

Potentiation of the hypotensive effect of adrenomedullin in pregnant rats

The hypotensive effect of adrenomedullin, a potent vasodilator peptide, was examined in conscious pregnant (6, 13 and 20 days of pregnancy) and non-pregnant rats. The intravenous administration of adrenomedullin (0.01-3.0 nmol/kg) produced a dose-dependent depressor response in pregnant and non-pregnant rats. At low doses (0.01-0.1 nmol/kg), the maximum decrease in blood pressure was significantly higher in pregnant rats (20 days pregnant) than in non-pregnant rats. At high doses, no significant difference was observed between the two groups. Furthermore, the administration of adrenomedullin did not significantly affect the basal mean blood pressure (MBP) at any dose when compared to the non-pregnant group at 6 and 13 days of pregnancy. In the ovariectomized rats, the depressor responses in 17beta-estradiol-treated, progesterone-treated and 17beta-estradiol+progesterone-treated rats were not significantly different from that in the control rats, suggesting that the augmented effect on the depressor response to adrenomedullin in pregnant rats may not be due to hormonal changes during pregnancy. The adrenomedullin receptor mRNA level of the descending thoracic aorta was significantly higher in the late-pregnancy rats (20 days of pregnancy). However, the levels did not show any difference between the early-pregnant rats (6 and 13 days of pregnancy) and the non-pregnant rats. These findings suggested that the changes in the depressor response to adrenomedullin which occur at term in pregnant rats may be mediated by changes of adrenomedullin receptor gene expression rather than by sex hormones.

TATA-Binding protein-interacting protein 120, TIP120, stimulates three classes of eukaryotic transcription via a unique mechanism

We previously identified a novel TATA-binding protein (TBP)-interacting protein (TIP120) from the rat liver. Here, in an RNA polymerase II (RNAP II)-reconstituted transcription system, we demonstrate that recombinant TIP120 activates the basal level of transcription from various kinds of promoters regardless of the template DNA topology and the presence of TFIIE/TFIIH and TBP-associated factors. Deletion analysis demonstrated that a 412-residue N-terminal domain, which includes an acidic region and the TBP-binding domain, is required for TIP120 function. Kinetic studies suggest that TIP120 functions during preinitiation complex (PIC) formation at the step of RNAP II/TFIIF recruitment to the promoter but not after the completion of PIC formation. Electrophoretic mobility shift assays showed that TIP120 enhanced PIC formation, and TIP120 also stimulated the nonspecific transcription and DNA-binding activity of RNAP II. These lines of evidence suggest that TIP120 is able to activate basal transcription by overcoming a kinetic impediment to RNAP II/TFIIF integration into the TBP (TFIID)-TFIIB-DNA-complex. Interestingly, TIP120 also stimulates RNAP I- and III-driven transcription and binds to RPB5, one of the common subunits of the eukaryotic RNA polymerases, in vitro. Furthermore, in mouse cells, ectopically expressed TIP120 enhances transcription from all three classes (I, II, and III) of promoters. We propose that TIP120 globally regulates transcription through interaction with basal transcription mechanisms common to all three transcription systems.

Attenuated hypotensive response to proadrenomedullin N-terminal 20 peptide in pregnant rats: modulation by steroid hormones

The hypotensive effect of proadrenomedullin N-terminal 20 peptide (PAMP) was examined in conscious pregnant (8, 14, and 20 days of pregnancy) and nonpregnant rats. Intravenous administration of PAMP (3-60 nmol/kg) produced a dose-dependent depressor response in both pregnant and nonpregnant rats. However, the maximum decrease in blood pressure was significantly attenuated in pregnant rats in mid- and late-gestation (14 and 20 days), but not in early gestation (8 days), than in nonpregnant rats. In ovariectomized rats, the depressor responses in 17beta-estradiol (E2)-treated, progesterone (P)-treated, and E2+P-treated rats were significantly attenuated compared with the control rats. We also demonstrated that treatment of sex hormones reduces the depressor response to PAMP in 8-day pregnant rats. In addition, we showed that treatment of sex hormone receptor antagonists partially prevents the attenuation of the depressor response to PAMP in 20 day pregnant rats. These findings suggested that the hypotensive response to PAMP was more attenuated in pregnant rats in mid- and late-gestation than in nonpregnant rats, and that the changes in depressor response that occur at term in pregnant rats may be mediated by sex hormones. PAMP may play some important role in cardiovascular regulation during pregnancy.

Heterogeneous nuclear RNA-ribonucleoprotein F binds to DNA via an oligo(dG)-motif and is associated with RNA polymerase II

BACKGROUND

The heterogeneous nuclear ribonucleoprotein F (hnRNP-F) is one of the constituents of the splicing-related hnRNP complex. Recent studies suggest that pre-mRNA modification and splicing factors are associated with transcriptional initiation factors and RNA polymerase II (RNA pol II) at a promoter, implying that pre-mRNA-engaged factors might be associated with a promoter.

RESULTS

We isolated a cDNA of rat hnRNP-F and expressed the recombinant protein. HnRNP-F selectively bound to oligo(dG) in constructions with other oligohomonucleotides. The ssDNA of an SV40 promoter sequence having the GC-boxes was bound to hnRNP-F, while hnRNP-F bound to the (G/C)-stretch as dsDNA. Consequently, hnRNP-F was designated as an oligo(dG)-binding protein. None of the RNA-binding domains (RBDs) in hnRNP-F were critical for the oligo(dG)-binding. In contrast, the GY-rich region that exists between RBD-II and -III exhibited an oligo(dG)-binding ability. We suggest that the GY-rich region is a novel DNA-binding motif. HnRNP-F was shown to contain two types of binding motifs for RNA and DNA. Additionally, we found that hnRNP-F was co-precipitated with RNA pol II. Interestingly, the RNA pol II holoenzyme also contained hnRNP-F. The tissue distribution profile of hnRNP-F was similar to that of both RNA pol II and TBP.

CONCLUSION

The above results suggest that hnRNP-F is associated with a transcriptional initiation apparatus that includes RNA pol II. The DNA-binding ability of hnRNP-F might facilitate the entry of pre-mRNA modification/splicing factors at a promoter.

Regional distribution of parkinsonism-preventing endogenous tetrahydroisoquinoline derivatives and an endogenous parkinsonism-preventing substance-synthesizing enzyme in monkey brain

1,2,3,4-Tetrahydroisoquinoline (TIQ) and 1-benzyl-1,2,3,4-tetrahydroisoquinoline (1BnTIQ), which exist in the brain of several mammalian species, are parkinsonism-inducing substances, and 1-methyl-1,2,3,4-tetrahydroisoquinoline (1MeTIQ), which is enzymatically synthesized in rat brain, is a parkinsonism-preventing substance. In this study, we examined the regional distribution of contents of TIQ, 1MeTIQ, and 1BnTIQ, and activity of 1MeTIQ-synthesizing enzyme in monkey brain. The TIQ and 1BnTIQ contents in cerebrum and substantia nigra, and the 1MeTIQ contents in striatum and substantia nigra were higher than those in other brain regions, and 1MeTIQ-synthetic activity was high in cerebrum and thalamus. We speculate that 1MeTIQ-synthesizing enzyme may play an important role in idiopathic Parkinson's disease.

Expression of adrenomedullin in feto-placental circulation of human normotensive pregnant women and pregnancy-induced hypertensive women

The adrenomedullin (AM) peptide and the expression of AM messenger RNA (mRNA) from feto-maternal tissues of 22 normotensive pregnant women and from 7 women with pregnancy-induced hypertension (PIH) during third-trimester were examined to clarify the pathophysiological features of PIH. Samples of the placenta, uterine muscle, umbilical artery, and fetal membranes were obtained from each patients under informed consent. The AM peptide was measured by a radioimmunoassay and the AM mRNA level was analyzed by Northern hybridization. The total immunoreactive AM (fmol/mg wet tissue) was significantly increased in the fetal membranes (1.95+/-0.20 vs. 3.03+/-0.44) and the umbilical artery (0.11+/-0.01 vs. 0.15+/-0.02) of the patients with PIH. On the other hand, the AM mRNA level was higher in the umbilical artery, and lower in the fetal membranes in the patients with PIH. The present results thus suggest that the changes in the expression of AM in fetal membrane and umbilical artery in PIH may play an important role in the fetal and maternal circulation.

Mucosal drug delivery using cellulose derivatives as a functional polymer

In order to develop nasal powder preparations with higher bioavailability for peptide delivery, the effect of a combination of hydroxypropyl cellulose (HPC) and microcrystalline cellulose (MCC) used as base materials and microenvironment for the drugs in the preparations was examined. Significant enhanced absorption of leuprolide, calcitonin and FITC-dextran was attained by the addition of a small amount of HPC to MCC. It is suggested that MCC works as an absorption enhancer by causing a locally high concentration of drugs in the vicinity of the mucosa surface. On the other hand, HPC works to increase retention of drugs on the nasal mucosa due to its gel-forming property. In comparison to the powder mixtures of MCC and HPC in which drugs were distributed to the MCC or HPC, selective distribution of drugs to MCC is shown to be a critical factor for enhancing nasal absorption. These results showed that the microenvironment of drugs in the functional base material could critically affect the nasal absorption of drugs.

Substance P causes adhesion of neutrophils to endothelial cells via protein kinase C

The sensory neuropeptide substance P is known to be involved in neurogenic inflammation. We examined the effect of substance P on neutrophil adhesion to human umbilical vein endothelial cells (HUVEC). Stimulation of HUVEC with substance P increased their adhesion to neutrophils in a time- and concentration (10(-10)-10(-7) M)-dependent manner. The adhesion was inhibited by the tachykinin NK1 receptor antagonist (+)-(2S,3S)-3-(2-Methoxybenzylamino)-2-phenylpiperidine (CP-99,994) and also by the protein kinase C inhibitors 1-(5-Isoquinolinesulfonyl)-2-methyl piperazine (H-7) and bisindolylmaleimide (BIM), but not by the protein kinase A inhibitor N-12-(p-Bromocinnamylamino) ethyl]-S-isoquinoline sulfonamide (H-89). These results indicate that substance P induces adhesion of neutrophils to HUVEC by activation of protein kinase C via the NK1 receptor on the HUVEC.

Autonomic function in hypertensive patients with neurovascular compression of the ventrolateral medulla oblongata

OBJECTIVE

To study whether abnormalities of autonomic function exist in patients with essential hypertension and neurovascular compression (NVC) of the medulla oblongata.

SUBJECTS AND METHODS

We studied 25 untreated patients with essential hypertension (13 men and 12 women, 27-74 years old). High-resolution magnetic resonance imaging and magnetic resonance angiography were used to detect NVC. Twenty-four-hour ambulatory monitoring of blood pressure and electrocardiogram were performed, and the power spectrum of heart rate variability was analyzed. On a separate day, various autonomic activity tests, including mental stress, hand grip, cold pressor, and Valsalva maneuver were performed. Baroreflex sensitivity was calculated from changes of blood pressure and R-R interval during phenylephrine infusion. A clonidine suppression test was also performed, with measurement of plasma catecholamine levels.

RESULTS

Fourteen of 25 patients (56%) had NVC (C group), and 11 patients did not have NVC (NC group). There were no significant differences in age, sex, family history, or duration of hypertension between the C and NC groups. Average 24-h systolic blood pressure was similar between the two groups, although 24-h diastolic blood pressure was higher in the C group than the NC group. Daytime, night-time, and 24-h heart rate was significantly higher in the C group than in the NC group. Night-time low frequency/high frequency ratio was slightly higher in the C group. Plasma norepinephrine levels were significantly higher (467 +/- 217 versus 299 +/- 122 pg/ml), and baroflex sensitivity was slightly lower in the C group than in the NC group. Responses of blood pressure and heart rate to mental stress, cold pressor, hand grip, Valsalva maneuver, phenylephrine infusion, and clonidine tests were not significantly different between the two groups.

CONCLUSIONS

NVC of the medulla oblongata was frequently found in patients with essential hypertension. Patients with NVC appeared to have enhanced sympathetic nervous activity compared with those without the compression.

Haemodynamic changes in non-alcoholic (viral) liver cirrhosis studied by computed tomography (CT) arterial portography and CT arteriography

AIMS

To evaluate haemodynamic and vascular changes in non-alcoholic (viral) cirrhosis on conventional computed tomography (CT), CT arteriography (CTA) and CT arterial portography (CTAP), and to determine the cause of the observed reticular stain on angiography.

METHODS

Using surgically resected liver specimens from 31 patients with viral hepatitis associated hepatocellular carcinoma, images of conventional CT, CTA, CTAP and the sinusoidal phase of hepatic arteriography were retrospectively analysed and compared with pathology of the non-cancerous portion of the liver.

RESULTS

Computed tomography arteriography showed inhomogeneous enhancement (diffuse, low-density nodules) in a total of 16 samples (52%); in eight of 10 (80%) cirrhotic livers, three of six (50%) precirrhotic livers, five of 12 (42%) livers with chronic active hepatitis and none of three with no active liver disease. The frequency of inhomogeneous enhancement became significantly higher with increasing severity of parenchymal damage (P < 0.05). In contrast, conventional CT and CTAP showed homogeneous enhancement in all 31 (100%) patients. There was no correlation between inhomogeneous enhancement on CTA and reticular staining on sinusoidal-phase hepatic angiograms. Inhomogeneous enhancement was frequently seen in patients with hepatitis B surface antigen and/or anti-hepatitis C virus antibody compared with those without them (P < 0.05).

CONCLUSION

The CTA was much more sensitive in detecting haemodynamic changes in the cirrhotic liver than CTAP, conventional CT and sinusoidal-phased hepatic angiography. Further study is required to clarify the mechanism of inhomogeneous enhancement on CTA and homogeneous enhancement on CTAP seen in cirrhosis.

Multiple mammalian proteasomal ATPases, but not proteasome itself, are associated with TATA-binding protein and a novel transcriptional activator, TIP120

BACKGROUND

SUG1 belongs to proteasomal ATPase. Previous studies have demonstrated that SUG1 is associated with TBP. It is assumed to be involved in transcriptional regulation in addition to proteolysis. In this study, we investigated the association of mammalian SUG1 with TBP in more detail.

RESULTS

Pull-down experiments with TBP revealed multiple TBP-interacting proteins (TIPs) that were recovered dependent upon the presence of C-terminal conserved domain of TBP. By 2-D electrophoresis, we identified SUG1 in TIPs. By using far-Western analysis, we identified two proteins that could directly bind to TBP: SUG1 and another proteasomal ATPase (S4). Protein microsequencing and Western blotting identified all the remaining proteasomal ATPases (MSS1, TBP1, TBP7, and SUG2) in the TIP preparations. We present evidence that TBP and at least SUG1, MSS1, and S4 form a complex in the cell. However, no evidence of association of TBP with the 26S proteasome or its 19S regulatory unit was obtained. The molecular mass of the TBP/ATPases-complex, which also included a novel transcription regulatory factor, TIP120, was estimated to be approximately 800 kDa.

CONCLUSION

These results suggest that there is a novel multisubunit complex containing TBP and proteasomal ATPases. Based on our findings, we hypothesize that proteasomal ATPases are involved in transcriptional regulation in addition to proteolysis.

Association of the rat heterogeneous nuclear RNA-ribonucleoprotein F with TATA-binding protein

Heterogeneous nuclear ribonucleoprotein F (hnRNP-F) has been shown to be a pre-mRNA splicing factor. Recent studies have uncovered the coordination of synthesis of pre-mRNA and its processing, including post-transcriptional modification and splicing. Here, we present evidence for an association between a splicing factor, hnRNP-F, and TATA-binding protein (TBP), which is an essential factor needed for transcription initiation. An affinity detection experiment revealed hnRNP-F in the preparation of TBP-interacting proteins. HnRNP-F was associated with TBP in nuclear extracts and was capable of direct binding to TBP in vitro. These results suggest that hnRNP-F is associated with TBP in the cell. HnRNP-F was observed in abundance in the thymus, spleen and testis, and its distribution pattern was similar to that of TBP, implying a functional coordination of transcription and splicing. We assume that the splicing machinery is associated with the transcription apparatus as a prerequisite prior to transcriptional elongation.

TIP120B: a novel TIP120-family protein that is expressed specifically in muscle tissues

TATA-binding protein (TBP) forms complexes with various nuclear proteins and plays roles in all eukaryotic transcription. We previously identified TBP-interacting protein 120 (TIP120) from rat liver. TIP120 stimulates in vitro transcription generally. Homologs of TIP120 exist in various higher eukaryotes including D. melanogaster, C. elegans, and A. thaliana. Here, we isolated cDNA of a novel rat TIP120-like protein, named TIP120B. Rat TIP120B was composed of 1,235 amino acids and was 60% identical to the original TIP120 (re-named TIP120A). However, TIP120B gene was expressed specifically in the muscle tissues, which was contrary to the ubiquitous expression of TIP120A. Moreover, TIP120B protein was observed exclusively in the muscle tissues. TIP120B is therefore suggested to be a muscle-specific protein. Northern blot analysis of the mouse embryo revealed that the expression of TIP120B was temporarily increased during the embryogenesis, whereas TIP120A maintained a constant expression level. Pull-down assay using GST-fused TBP demonstrated that TBP specifically associated with TIP120B in the nuclear extract. These results indicate that TIP120B is a muscle-specific TIP120 family protein and can also interact with TBP. TIP120B is supposed to have a specific role in muscle tissues, which may be diffrerent from that of TIP120A.

TIP49b, a new RuvB-like DNA helicase, is included in a complex together with another RuvB-like DNA helicase, TIP49a

We previously reported that TIP49a is a novel mammalian DNA helicase showing structural similarity with the bacterial recombination factor RuvB. In this study, we isolated a new TIP49a-related gene, termed TIP49b, from human and yeast cells. TIP49b also resembled RuvB, thus suggesting that TIP49a and TIP49b are included in a gene family. Like TIP49a, TIP49b was abundantly expressed in the testis and thymus. Enzyme assays revealed that TIP49b was an single-stranded DNA-stimulated ATPase and ATP-dependent DNA helicase. Most of the enzymatic properties of TIP49b were the same as those of TIP49a, whereas the polarity of TIP49b DNA helicase activity (5' to 3') was the opposite to that of TIP49a. TIP49b and TIP49a bound to each other and were included in the same complex of approximately 700 kDa in a cell. We found that TIP49b was an essential gene for the growth of Saccharomyces cerevisiae, as is the TIP49a gene, suggesting that TIP49b does not complement the TIP49a function and vice versa. From these observations, we suggest that TIP49b plays an essential role in the cellular processes involved in DNA metabolism.

Analysis of the chicken TBP-like protein(tlp) gene: evidence for a striking conservation of vertebrate TLPs and for a close relationship between vertebrate tbp and tlp genes

TLP (TBP-like protein), which is a new protein dis-covered by us, has a structure similar to that of the C-terminal conserved domain (CCD) of TBP, although its function has not yet been elucidated. We isolated cDNA and genomic DNA that encode chicken TLP (cTLP) and determined their structures. The predicted amino acid sequence of cTLP was 98 and 91% identical to that of its mammalian and Xenopus counterparts, respectively, and its translation product was ubiquitously observed in chicken tissues. FISH detection showed that chicken tlp and tbp genes were mapped at 3q2.6-2.8 and 3q2.4-2.6 of the same chromosome, respectively. Genome analysis revealed that the chicken tlp gene was spliced with five introns. Interestingly, the vertebrate tbp genes were also found to be split by five introns when we focused on the CCDs, and their splicing points were similar to those of tlp. On the contrary, another TBP-resembling gene of Drosophila, trf1, is split by only one intron, as is the Drosophila 's tbp gene. These results support our earlier assumption that vertebrate TLPs did not directly descend from Drosophila TRF1. On the basis of these results together with phylogenetical exam-ination, we speculate that tlp diverged from an ancestral tbp gene through a process of gene duplication and point mutations.

Mitochondrial thioredoxin reductase in bovine adrenal cortex its purification, properties, nucleotide/amino acid sequences, and identification of selenocysteine

Mitochondrial thioredoxin reductase was purified from bovine adrenal cortex. The enzyme is a first protein component in the mitochondrial thioredoxin-dependent peroxide reductase system. The purified reductase exhibited an apparent molecular mass of 56 kDa on SDS/PAGE, whereas the native protein was about 100 kDa, suggesting a homodimeric structure. It catalysed NADPH-dependent reduction of 5, 5'dithiobis(2-nitrobenzoic acid) and thioredoxins from various origins but not glutathione, oxidized dithiothreitol, DL-alpha-lipoic acid, or insulin. Amino acid and nucleotide sequence analyses revealed that it had a presequence composed of 21 amino acids which had features characteristic of a mitochondrial targeting signal. The amino acid sequence of the mature protein was similar to that of bovine cytosolic thioredoxin reductase (57%) and of human glutathione reductase (34%) and less similar to that of Escherichia coli (19%) or yeast (17%) enzymes. Human and bovine cytosolic thioredoxin reductase were recently identified to contain selenocysteine (Sec) as one of their amino acid constituents. We also identified Sec in the C-terminal region of mitochondrial (mt)-thioredoxin reductase by means of MS and amino acid sequence analyses of the C-terminal fragment. The four-amino acid motif, Gly-Cys-Sec-Gly, which is conserved among all Sec-containing thioredoxin reductases, probably functions as the third redox centre of the enzyme, as the mitochondrial reductase was inhibited by 1-chloro-2,4-dinitrobenzene, which was reported to modify Sec and Cys covalently. It is known that mammalian thioredoxin reductase is different from bacterial or yeast enzyme in, for example, their subunit molecular masses and domain structures. These two different types of enzymes with similar activity are suggested to have evolved convergently. Our data clearly show that mitochondria, which might have originated from symbiotic prokaryotes, contain thioredoxin reductase similar to the cytosolic enzyme and different from the bacterial one.

On the maximum size of proteins to stay and fold in the cavity of GroEL underneath GroES

GroEL encapsulates non-native protein in a folding cage underneath GroES (cis-cavity). Here we report the maximum size of the non-native protein to stay and fold in the cis-cavity. Using total soluble proteins of Escherichia coli in denatured state as binding substrates and protease resistance as the measure of polypeptide held in the cis-cavity, it was estimated that the cis-cavity can accommodate up to approximately 57-kDa non-native proteins. To know if a protein with nearly the maximum size can complete folding in the cis-cavity, we made a 54-kDa protein in which green fluorescent protein (GFP) and its blue fluorescent variant were fused tandem. This fusion protein was captured in the cis-cavity, and folding occurred there. Fluorescence resonance energy transfer proved that both GFP and blue fluorescent protein moieties of the same fused protein were able to fold into native structures in the cis-cavity. Consistently, simulated packing of crystal structures shows that two native GFPs just fit in the cis-cavity. A fusion protein of three GFPs (82 kDa) was also attempted, but, as expected, it was not captured in the cis-cavity.