Molecular characterization of the gene encoding the precursor protein of diapause hormone and pheromone biosynthesis activating neuropeptide (DH-PBAN) of the silkworm, Bombyx mori and its distribution in some insects

The diapause hormone is a 24 amino acid peptide amide which induces embryonic diapause of the silkworm, Bombyx mori. Diapause hormone, pheromone biosynthesis activating neuropeptide, and other three neuropeptides of FXPRL amide peptide family have been shown to be generated from a polyprotein precursor which is encoded by a single mRNA. We have cloned the genomic sequence encoding the precursor protein of diapause hormone-pheromone biosynthesis activating neuropeptide (DH-PBAN) by using a DH-PBAN cDNA as a probe, and analyzed its structure. The gene comprised six exons interspersed by five introns. The diapause hormone sequence along with a signal sequence was encoded in the first and second exons, and the pheromone biosynthesis activating neuropeptide was in the fourth and fifth exons. The major transcription initiation site of the gene was localized at 25 bp upstream from the translation start site. A single copy of this gene was present in a haploid genome. The 5'-upstream region of the gene contained a sequence similar to the ecdysone responsive element of Drosophila hsp 23 gene, and five decanucleotide motifs, which shared the homeodomain binding core sequence, TAAT. Genomic Southern analysis on DNA from some insect species other than the silkworm showed positive bands which hybridized with DH-PBAN cDNA of the silkworm. Thus, the DH-PBAN-like gene seems to be widely distributed in insects.

[A case of schwannoma of intrathoracic right phrenic nerve]

An abnormal shadow was pointed out on the roentgenogram of a 41-year-old woman. CT scan revealed a tumor, 3 cm in diameter, at the right mediastinum. The tumor originated from a right phrenic nerve was removed surgically on May 20th, 1993. Histopathological examination revealed that the tumor was a schwannoma. Of 138 mediastinum tumors that we vesected in the last 10 years, 24 were neurogenic tumors (17%), and only one of which was originated from a phrenic nerve (4.1%). This rare case is reported with review of the literature.

[2'-5' olygoadenylate synthetase activity in peripheral facial paralysis]

Interferons are produced in response to viral infection and play an important part in defense by their antiviral effects. An interferon-induced enzyme, 2'-5' oligoadenylate synthetase (2-5AS) also takes an important part of the system of defense against viral infections, and its activity elevates in nonspecific viral infections. This study was designed to evaluate the usefulness of examining serum 2-5AS activity and peripheral blood WBC 2-5AS (WBC 2-5AS) as diagnostic aids of viral infections that cause facial paralysis. Samples were obtained from 83 patients with Bell's palsy, 20 with Ramsay Hunt syndrome, 74 healthy individuals, and a total of 177 subjects. In 177, we measured serum 2-5AS level in 123 subjects, WBC 2-5AS level in 57, and both in 25. Serum 2-5AS levels in Bell's palsy (60 cases) ranged from 20 to 146 pmol/dl (average: 38.5). The range in Ramsay Hunt syndrome (13) was 20-333 (average: 59.0), and in healthy controls (50), it was 20-128 (average: 41.4). WBC 2-5AS level ranged from 20 to 5900 pmol/dl (average: 733.2) in Bell's palsy (23 cases), from 20-4540 (average: 1371.4) in Ramsay Hunt syndrome (7), and from 20-903 (average: 294.5) in healthy individuals (24). There were no statistically significant differences in serum 2-5AS activities. Otherwise, there was significant difference (p < 0.01) between healthy individuals and Patients with Ramsay Hunt syndrome in WBC 2-5AS activity. In Bell's palsy, 3 cases (13.0%) with markedly high WBC 2-5AS levels existed.(ABSTRACT TRUNCATED AT 250 WORDS)

Urinary methylchloroform rather than urinary metabolites as an indicator of occupational exposure to methylchloroform

In order to compare methylchloroform (MC, or 1,1,1-trichloroethane) per se and its metabolites in urine as indicators of occupational exposure to this solvent, 50 male solvent workers were studied in the second half of a working week to evaluate the exposure-excretion relationship. The time-weighted average intensity of solvent exposure of individuals during an 8-h shift was monitored by personal diffusive sampling. Urine samples were collected near the end of the shift and were analyzed for MC and its metabolites [i.e., trichloroacetic acid (TCA), trichloroethanol (TCE) and total trichloro-compounds (TTC; the sum of TCA and TCE)] by head-space gas chromatography. MC per se, TCA, TCE, and TTC in urine correlated significantly (P < 0.01) with MC in ambient air, and among the four the correlation coefficient was highest for MC. The same result were obtained by multiple regression analysis in which ambient air MC was taken as the dependent variable and either the three indicators urinary MC, TCA, and TCE or the two indicators urinary MC and TTC were taken as independent variables. Taking the specificity and selectivity of the analyte as well as the simple and hazardous chemical-free procedure of analysis into consideration, it is concluded that MC is the analyte of choice as an indicator of occupational exposure to MC, when urine is selected as a specimen available by noninvasive sampling.

Analysis of protein-DNA and protein-protein interactions of centromere protein B (CENP-B) and properties of the DNA-CENP-B complex in the cell cycle

We previously reported that centromere protein B (CENP-B) forms a stable complex (designated complex A) containing two alphoid DNAs in vitro. Domains in the CENP-B polypeptide involved in the formation of complex A were determined in the present study with truncated derivatives expressed in Escherichia coli and in rabbit reticulocyte lysates. It was revealed by gel mobility shift analyses that polypeptides containing the NH2-terminal DNA-binding domain bind a DNA molecule as a monomer, while dimerizing at a novel hydrophobic domain in the COOH-terminal region of 59 amino acid residues. This polypeptide dimerization activity at the COOH-terminal region was also confirmed with the two-hybrid system in Saccharomyces cerevisiae cells. The results thus proved that CENP-B polypeptides form a homodimer at the COOH-terminal hydrophobic domain, each binding a DNA strand at their NH2-terminal domains. The dimerization and DNA-binding domains fall into two of the three completely conserved sequences found in human and mouse CENP-B, and complex A-forming activity was also detected in nuclear extracts of mouse cells. Metaphase-specific phosphorylation of CENP-B was also detected, but this had no effect on its complex A-forming activity. On the basis of the present results, we propose that CENP-B plays an important role in the assembly of specific centromere structures by forming unique DNA-protein complexes at the sites of CENP-B boxes on the centromeric repetitive DNA both in interphase nuclei and on mitotic chromosomes.

Human urinary kallikrein can generate angiotensin II from homologous renin substrates

We previously proposed the "kinin-tensin system," a unique vasoregulatory system that can produce both angiotensin II and kinins. To verify whether tissue kallikrein is a part of this system in humans, we examined the ability of human urinary kallikrein (HUK) to generate angiotensin (ANG) II directly from homologous renin substrates such as purified human angiotensinogen (AOGEN) and authentic human tridecapeptide renin substrate (13 RS). HUK released ANG II not only from ANG I but also directly from both AOGEN and 13RS at an optimum pH of 7.0. The amount of generated ANG II from 7.5 nmol of each of the three substrates at pH 7.0 was as follows: ANG I, 292.7 +/- 67.2; 13 RS, 1951.7 +/- 239.6; AOGEN, 2.2 +/- 0.3 (pmol/3h, n = 3 mean +/- SE). HUK cleaved Phe-His and His-Leu bonds in 13 RS, and Tyr-Ile and Phe-His bonds in ANG I. These results suggest that HUK is a part of the "kinintensin system", i.e., HUK can not only release kinins, but can also generate ANG II mainly through ANG I conversion and from AOGEN, the latter being a minor source of ANG II. Furthermore, HUK may play a role in regulating vascular tone under certain conditions in vivo.

Brain natriuretic peptide as a marker for hypertensive left ventricular hypertrophy: changes during 1-year antihypertensive therapy with angiotensin-converting enzyme inhibitor

PURPOSE

Secretion of brain natriuretic peptide (BNP), a cardiac hormone, is accelerated via hypertrophied ventricles in experimental hypertension. The present study examined whether regression of left ventricular (LV) hypertrophy by long-term treatment with an angiotensin-converting enzyme inhibitor (ACEI) affects plasma BNP concentration in patients with essential hypertension.

PATIENTS AND METHODS

Thirty-one hypertensive patients with LV hypertrophy were treated with ACEI (16 with enalapril; 15 with lisinopril) for 1 year. Serial changes were recorded in LV mass index, LV systolic function, and plasma concentrations of BNP and atrial natriuretic peptide (ANP).

RESULTS

ACEI therapy significantly reduced LV mass index at 6 months, and more so at 1 year. Septal and posterior wall thicknesses were also reduced. Plasma BNP and ANP were markedly elevated at study entry, but only BNP levels correlated with LV mass index. Both peptide levels declined after 6 months, and this decline was enhanced at 1 year. There was a close relation between BNP decline and LV mass index reduction overall and with enalapril and lisinopril separately. Changes in ANP and in LV mass index were not related.

CONCLUSION

Long-term ACEI therapy can reduce elevated plasma BNP. In this study, changes in BNP reflected the magnitude of regression of LVH. Plasma BNP may be a useful marker for LVH during antihypertensive therapy in patients with essential hypertension and LVH.

Behavioral and electroencephalographic properties of duloxetine (LY248686), a reuptake inhibitor of norepinephrine and serotonin, in mice and rats

Duloxetine is a dual inhibitor of norepinephrine and serotonin reuptake. Duloxetine (3.13-50 mg/kg p.o.) significantly prevented tetrabenazine (1 and 50 mg/kg s.c.)-induced ptosis in mice and rats. Moreover, duloxetine (1.56-12.5 mg/kg p.o.) also inhibited reserpine (1 mg/kg s.c.)-induced hypothermia in mice. When duloxetine (12.5-100 mg/kg p.o.) and 5-hydroxytryptophan (80 and 100 mg/kg i.p.), a precursor of serotonin, were administered simultaneously to mice and rats, head movement behavior and tremor were observed. In addition, duloxetine (25-100 mg/kg p.o.) significantly attenuated immobility in forced swimming in mice, as equally effective as commonly used antidepressant drugs. Duloxetine (12.5-25 mg/kg p.o.) significantly decreased rapid eye movement sleep and slow-wave deep sleep and increased the awake period, as shown in the rat EEG. However, duloxetine (25-200 mg/kg p.o.) did not affect salivation and lacrimation induced by oxotremorine (1 mg/kg s.c.), a cholinergic agonist, whereas it (25-50 mg/kg) reduced the oxotremorine-induced tremor in part. These results indicated that duloxetine produced behavioral and electroencephalographic responses resulting from the inhibition of norepinephrine and serotonin reuptake in vivo, and that it had a weak anticholinergic action. Therefore, duloxetine may be clinically useful as an antidepressant.

Optokinetic after-nystagmus under prolonged alteration in the direction of gravity

Optokinetic nystagmus (OKN) and after-nystagmus (OKAN) show different responses depending on the direction of gravity with respect to the head and body. In 13 normal healthy persons (10 experimental and 3 control subjects), we studied the OKAN evoked by horizontal and vertical stimuli, in upright, side-lateral, and repeated upright positions along a time course of more than 6 h. The results showed continuous modifications of OKAN, the degree increasing with time. Lateral tilt produced different effects on the intrinsic vertical and horizontal optokinetic oculomotor systems.

[Ménière's disease in the aged]

Twenty-one patients with Ménière's disease over the age of seventy years were classified into two groups. Group I: Eleven patients who had their first vertiginous attack after the age of sixty-nine (nine males, two females). Group II: Ten patients who had a long history of Ménière's disease and had been followed until the age of 72 to 79 years of age (seven males, three females). In Group I there were repeated attacks of vertigo accompanied by fluctuations in hearing in the low and middle tone range, though not so severe or frequent as in the typical active stage of Ménière's disease in younger patients. Most patients in this group were still working as managers of a company or institution. Other patients had been taking care of a sick spouse for several years. In Group II, the patients rarely experienced severe vertiginous attacks, however, hearing became rapidly impaired in most cases after they reached around 70 years of age. Progression of their hearing impairment was so severe that it was considered beyond the loss of acoustic function attributable to physiological aging. The importance of Ménière's disease among the aged is increasing as a result of the rapid increase in the aged population. Based on long-term observations of Ménière's disease, we have concluded that there are at least two clinically different types of disease in the aged, then especially age of onset and the duration of the disease of the each patient must be heeded.

Enhancement by zinc of ATP-evoked dopamine release from rat pheochromocytoma PC12 cells

The effects of zinc (Zn2+) on ATP-evoked dopamine release was investigated in rat pheochromocytoma PC12 cells. Zn2+ potentiated the dopamine release evoked by 30 microM ATP in a concentration-dependent manner over a concentration range from 3 to 300 microM. High concentration of Zn2+ (> 1 mM) inhibited the release. Zn2+ (10 microM) shifted the concentration-response curve of the ATP-evoked dopamine release to the left without affecting the maximal response. The dopamine release evoked by 40 mM KCl was not affected by Zn2+ (1-100 microM), whereas high concentration of Zn2+ ( > 300 microM) attenuated the response. The dopamine release evoked by 30 microM ATP in the presence of 10 microM Zn2+ were suppressed by suramin (30 microM), an antagonist to P2-purinoceptors, to an extent similar to that in the absence of Zn2+. Zn2+ (1-100 microM) enhanced the ATP-evoked increase in intracellular Ca2+ concentration ([Ca]i) in the cells. The Ca2+ responses to ATP in the presence and absence of Zn2+ were abolished by external Ca(2+)-depletion. Under whole-cell voltage-clamp, Zn2+ (10 microM) augmented by two-fold the peak amplitude of an inward current evoked by 30 microM ATP. Taken together, it is suggested that Zn2+ enhances the ATP-evoked dopamine release by increasing sensitivity to ATP. The enhancement may be due to the augmentation of ATP-gated Ca(2+)-influx, but not due to modulation of cellular machinery downstream to [Ca]i rise. The enhancement of the ATP-mediated responses may underlie modulation by Zn2+ of physiological functions in various types of neuronal cells.

Stage-dependent and temperature-controlled expression of the gene encoding the precursor protein of diapause hormone and pheromone biosynthesis activating neuropeptide in the silkworm, Bombyx mori

Embryonic diapause and sex pheromone biosynthesis in the silkworm, Bombyx mori, are, respectively, induced by diapause hormone (DH) and pheromone biosynthesis activating neuropeptide (PBAN), which are produced in the subesophageal ganglion from a common polyprotein precursor (DH-PBAN precursor) encoded by a single gene (DH-PBAN gene). Using DH-PBAN cDNA as a probe, we quantitatively measured DH-PBAN mRNA content throughout embryonic and postembryonic development and observed the effects of incubation temperature, which is a key factor for determination of diapause, on DH-PBAN gene expression. The silkworm, which is programmed to lay diapause eggs by being incubated at 25 degrees C, showed peaks of DH-PBAN mRNA content at five different stages throughout the life cycle: at the late embryonic stage, at the middle of the fourth and the fifth larval instars, and at early and late stages of pupal-adult development. In the non-diapause type silkworms programmed by a 15 degrees C incubation, only the last peak of DH-PBAN mRNA in pupal-adult development was found, and the other peaks were absent. Furthermore, interruption of the incubation period at 25 degrees C by incubation at 15 degrees C decreased both DH-PBAN mRNA content in mature embryos and in subesophageal ganglia of day 3 pupae and the incidence of diapause eggs. Thus, there were two types of regulatory mechanisms for DH-PBAN gene expression. One is a temperature-controlled expression that is responsible for diapause induction, and the other is a temperature-independent, stage-dependent expression related to pheromone production.

Rapid determination of dabsylated hydroxyproline from cultured cells by reversed-phase high-performance liquid chromatography

A high-performance liquid chromatographic method was modified for the determination of hydroxyproline in cultured cells derived from rat liver. First, the primary amino group in the cell hydrolysate was blocked with o-phthalaldehyde, then the secondary amino group was derivatized with 4-dimethylaminoazobenzene-4'-sulfonyl chloride (dabsyl chloride). The dabsylated sample was treated with ethyl acetate to obtain a simple chromatographic elution profile of the cell hydrolysate. Dabsylhydroxyproline and proline were separated from other compounds by high-performance liquid chromatography in the gradient elution mode, and eluted at 4.71 and 8.00 min, respectively. The method was applied to the determination of hydroxyproline contained in cultured cells, the result being 25.4 +/- 3.6 pmol/microgram.

Involution of mouse mammary glands in whole organ culture: a model for studying programmed cell death

The DNA fragmentation and gene expression patterns of involuting mouse mammary glands were compared to mammary glands in whole organ culture induced to involute by the withdrawal of lactogenic hormones. Non-random DNA degradation was observed both in vivo and in vitro, indicating that the withdrawal of lactogenic hormones triggers a program of epithelial cell death. Similar patterns of gene expression for the milk protein beta-casein and the apoptosis associated factors TGF-beta 1, TGF-beta 2 and TGF-beta 3 were observed in vivo and in vitro. These results indicate that the withdrawal of lactogenic hormones is responsible for decreased milk synthesis, epithelial cell death and tissue restructuring and that whole organ culture of mouse mammary glands is a useful model for studying the molecular events involved in these processes during involution.

Detection of messenger RNA for gonadotropin-releasing hormone (GnRH) but not for GnRH receptors in mouse mammary glands

While gonadotropin-releasing hormone (GnRH), GnRH-like, or GnRH receptor (GnRH-R) have been reported to exist in several tissues other than brain or anterior pituitary, there is no report concerning GnRH or GnRH-R gene expression in the normal mammary gland. In order to define the production of GnRH as well as GnRH-R in the mammary gland at the molecular level we examined their gene expression in various functional stages of the mouse mammary gland using the reverse transcriptase-polymerase chain reaction (RT-PCR). GnRH mRNA transcripts were found in mouse mammary glands of mid-pregnant, lactating, and 3, 6, 9 days post-lactational mice, whereas GnRH-R mRNA transcripts were not detected in mammary glands of any functional stage. These results suggest a possible biological role of GnRH in mammary gland.

Diagnostic usefulness of chest computed radiography--film versus cathode-ray tube images

Seventy-one plain chest images obtained by computed radiography (CR) with an imaging plate were interpreted on film and two kinds of cathode-ray tube (CRT) monitors installed separately at two facilities (1,024 x 1,536 pixels, 8 bits, and 1,024 x 1,280 pixels, 10 bits) by 20 radiologists and four chest internists. The clinical categories of these 71 cases included pulmonary nodules and interstitial abnormalities. Image reading sessions were held over a total of 4 days, ie, 2 days and then another 2 days, 3 weeks later. Twenty-four observers formed four groups with six members each. Two groups read either films or CRT images at one of the two facilities. In the second experiment, 26 of 71 images were compressed at 10:1, 19 of 71 were compressed at 20:1, and 26 were not compressed. Analyses of the areas under the receiver-operating characteristic curves showed no significant differences in detection of pulmonary abnormalities between film and CRT. In detecting interstitial pulmonary abnormalities, film was more sensitive than CRT monitor. There were no significant differences in observers' performances between the two different kinds of CRT workstation. Subjective evaluation of image quality showed that images irreversibly compressed to the ratios of 10:1 and 20:1 were inferior to original images. Although further considerations are needed with regard to spatial resolution requirements, image processing, and image compression, the utilization of CR CRT image as a substitute for CR film image will be possible.

[Familial Alzheimer's disease in Japanese population]

We ascertained 56 related cases with early onset familial Alzheimer's disease (EOFAD; mean age of onset < 65 years) and 10 related cases with late onset familial Alzheimer's disease (LOFAD; mean age of onset > or = 65 years) through a questionnaire administered to neuro-psychiatric and medical school hospitals in Japan and through a review of cases in Japanese literature. Mean age of onset and death (+/- S.D.) of EOFAD were 43.4 +/- 8.6 years (n = 94) and 51.1 +/- 10.5 years (n = 85), respectively. Distributions of the age-onset were relatively constant within a family but significantly different between families. Our result may suggest that clinical differences between families represent genetic heterogeneity at the molecular level. Six out of 32 related cases of with EOFAD showed the 717 Val-->Ile mutation of beta/A4 amyloid precursor protein (APP) gene. This result suggests that the frequency of this mutation in Japanese population is higher than in Caucasian and allelic the existenced heterogeneity, in Japanese EOFAD.

[Optimal concentration of contrast medium in helical CT of the thorax]

In 99 examinations of 89 patients, we took CT images of the chest after administering one of three concentrations of contrast medium (iohexol 140 mgI/ml, 240 mgI/ml, 300 mgI/ml) to determine the optimal iodo-concentration for intravenous contrast enhancement in spiral CT. Attenuation values of the superior vena cava, ascending aorta, descending aorta, and pulmonary artery were measured to evaluate the degree of contrast enhancement. Five radiologists judged the image quality by scoring factors such as vascular opacification, delineation of the lung and chest wall, detectability of calcification, lymphadenopathy and pulmonary nodules, and the presence of artifacts. The relationships between the iodo-concentration and the scores were analyzed statistically. The higher the iodo-concentration of the contrast medium administered, the stronger the vascular structures were opacified. There was also a concurrent improvement in the detection of lymphadenopathy. However, artifacts appeared on the administration route as a result of the high-concentration contrast medium, and the image quality was degraded. Among the three groups, iohexol 240 mgI/ml exhibited the best performance, namely, good image quality, so that a high degree of contrast enhancement of the vasculature was obtained with few artifacts due to the contrast medium. However, we believe that iohexol 140 mgI/ml presents no significant problems in routine studies.

Subtle increase in leukocyte counts in association with drinking and smoking habits

Peripheral leukocyte counts were examined in venous blood of more than 800 male workers exposed to toluene, xylenes, a combination of the two, or neither. Information on the social habits of smoking and drinking was obtained in an occupational health interview. The analysis showed that smoking (15 cigarettes/day on average) induced a significant increase (by 7%) in leukocyte counts, and that an additional increase was induced when the drinking habit was coupled with smoking. Drinking alone tended to increase the leukocyte counts but the effect was statistically nonsignificant, possibly because the number of nondrinking smokers was limited. The study stresses the importance of paying attention to smoking and drinking habits when evaluating hematological parameters such as peripheral leukocyte counts in solvent-exposed workers.

The regulation of cholesteryl ester metabolism by 17 beta-estradiol in macrophages. Activation of neutral cholesterol esterase

The mechanism for antiatherogenic effects of 17 beta-estradiol (E2) was investigated in J774 A.1 cells incubated with beta-VLDL. E2 at physiological concentrations (0.25 and 2.5 nM) inhibited an accumulation of cellular cholesteryl esters and enhanced their hydrolysis in foam cells. These phenomena were preceded by activation of neutral cholesterol esterase through an increase in cyclic AMP-dependent protein kinase activity. 17 alpha-estradiol, progesterone, and testosterone lacked such stimulatory effects on neutral cholesteryl esterase.

Nucleotide sequence and transcriptional analysis of the DNA polymerase gene of Bombyx mori nuclear polyhedrosis virus

A gene encoding a putative DNA polymerase (pol) of Bombyx mori nuclear polyhedrosis virus (BmSNPV) was cloned and sequenced. The gene included an open reading frame (ORF) encoding a polypeptide of 988 amino acids with a predicted molecular mass of 114.65 kDa. The deduced amino acid sequence of the BmSNPV pol ORF showed an overall identity of 96 and 45% to those of the Autographa californica NPV (AcMNPV) pol ORF and the Lymantria dispar NPV pol ORF, respectively, and contained sequences conserved in a variety of eukaryotic and viral replicative DNA polymerases. The BmSNPV pol lacked a canonical TATAA element but contained a G+C-rich sequence in the transcriptional initiation region. Analyses by Northern blot hybridization, RNase protection assay, primer extension, and 3' and 5' RACE (rapid amplification of cDNA ends) showed that at least seven different transcripts of approximately 3.1 kb that shared a common 3' end were expressed from the BmSNPV pol. The expression of these transcripts from BmSNPV pol was regulated differentially during virus infection. Transcription of five of the seven species initiated in the close vicinity of and within the motif 5'-GCGTGCT-3'. One transcript placed its initiation site within the motif 5'-AGAGCGT-3' and the remaining one within the motif 5'-GGCGGTGG-3'. The motifs 5'-GCGTGCT-3' and 5'-AGAGCGT-3' have been identified in pol and other genes of AcMNPV as conserved sequences containing transcriptional initiation sites, whereas the motif 5'-GGCGGTGG-3', which is arranged as a direct repeat in BmSNPV pol but not in AcMNPV pol, has not been defined as the sequence responsible for transcriptional initiation sites. The BmSNPV pol transcripts were detectable at 2 hr postinfection (p.i.), peaked at 10 hr p.i., and declined to a low level by 18 hr p.i. The expression of BmSNPV pol was not inhibited but delayed dramatically by the protein synthesis inhibitor cycloheximide upon treatment of infected cells, whereas aphidicolin, an inhibitor of DNA polymerase, inhibited BmSNPV pol transcription. These results suggest a complicated and unique mechanism for the regulation of BmSNPV pol expression.