Nucleotide and amino acid sequence analysis of the porcine adenovirus 23K protein

The genomic location of the viral encoded protease (23K) of porcine adenovirus serotype 3 (PAV3) was determined and the appropriate fragment cloned and sequenced. An open reading frame (ORF) coding for a polypeptide of 203 amino acids and a calculated molecular weight of 23.3 kDa was found. The ORF was situated in a position similar to that of the human adenovirus 23K, that is, between a putative stop codon for the hexon gene and the polyadenylation signal, AATAAA, for the late region 3. Amino acid sequence alignment of the predicted polypeptide with the sequences of the 23K proteins from other mammalian adenoviruses revealed homology of between 50% and 60% for all except the bovine adenovirus type 7, which displayed appreciable variance from the PAV3 putative 23K with an overall sequence homology of approximately 35%. Conserved cysteine, histidine and proline residues believed to be important in the activity of the 23K protein of human adenoviruses were also present in the PAV3 protein. The genomic location and amino acid sequence of the characterised reading frame suggests that this gene is that of the 23K protein of PAV3.

Natural history of untreated cytomegalovirus retinitis

Cytomegalovirus infection is common in patients with AIDS, and often causes retinitis. Treatment is rarely curative, but the progression of retinitis is delayed. The untreated course of cytomegalovirus retinitis in AIDS is unknown. We report a 35-year-old man with retinitis who refused treatment. Retinitis resulted in blindness within 6 months. Measurement of cytomegalovirus genomes showed an increasing viral load in blood and urine.

Functions of the C-terminal domain of CTP: phosphocholine cytidylyltransferase. Effects of C-terminal deletions on enzyme activity, intracellular localization and phosphorylation potential

The role of the C-terminal domain of CTP: phosphocholine cytidylyltransferase (CT) was explored by the creation of a series of deletion mutations in rat liver cDNA, which were expressed in COS cells as a major protein component. Deletion of up to 55 amino acids from the C-terminus had no effect on the activity of the enzyme, its stimulation by lipid vesicles or on its intracellular distribution between soluble and membrane-bound forms. However, deletion of the C-terminal 139 amino acids resulted in a 90% decrease in activity, loss of response to lipid vesicles and a significant decrease in the fraction of membrane-bound enzyme. Identification of the domain that is phosphorylated in vivo was determined by analysis of 32P-labelled CT mutants and by chymotrypsin proteolysis of purified CT that was 32P-labelled in vivo. Phosphorylation was restricted to the C-terminal 52 amino acids (domain P) and occurred on multiple sites. CT phosphorylation in vitro was catalysed by casein kinase II, cell division control 2 kinase (cdc2 kinase), protein kinases C alpha and beta II, and glycogen synthase kinase-3 (GSK-3), but not by mitogen-activated kinase (MAP kinase). Casein kinase II phosphorylation was directed exclusively to Ser-362. The sites phosphorylated by cdc2 kinase and GSK-3 were restricted to several serines within three proline-rich motifs of domain P. Sites phosphorylated in vitro by protein kinase C, on the other hand, were distributed over the N-terminal catalytic as well as the C-terminal regulatory domain. The stoichiometry of phosphorylation catalysed by any of these kinases was less than 0.2 mol P/mol CT, and no effects on enzyme activity were detected. This study supports a tripartite structure for CT with an N-terminal catalytic domain and a C-terminal regulatory domain comprised of a membrane-binding domain (domain M) and a phosphorylation domain (domain P). It also identifies three kinases as potential regulators in vivo of CT, casein kinase II, cyclin-dependent kinase and GSK-3.

Molecular evolution of infectious laryngotracheitis virus (ILTV; gallid herpesvirus 1): an ancient example of the Alphaherpesviridae?

An analysis of two essential genes of infectious laryngotracheitis virus (ILTV), glycoprotein D (gD) and the immediate early gene, herpes simplex virus homologue ICP27, was performed with the equivalent gene homologues from several alphaherpesviruses. Amino acid (aa) sequence analysis revealed that these ILTV genes shared limited homology to other alphaherpesvirus equivalents and were distinct from the two other avian herpesviruses, Marek's disease virus (MDV) and herpesvirus of turkeys (HVT). Simplex and varicella group viruses are clearly separate from the avian group. The amino acid sequences of these ILTV genes will be presented with comparisons to the homologues from other alphaherpes viruses, contributing further evidence of the evolution of this group of viruses from a common progenitor and that ILTV could be an ancient example of the Alphaherpesvirinae.

Use of the polymerase chain reaction to detect genomes of human immunodeficiency virus and cytomegalovirus in post-mortem tissues

The polymerase chain reaction (PCR) was used to amplify a 149 base-pair region of the cytomegalovirus (CMV) genome and a 551 base-pair region of the HIV-1 proviral long terminal repeat (LTR) present in DNA extracted from post-mortem tissue. Multiple tissues (n = 116) obtained from 16 patients which were subjected to PCR were also subjected to cell culture and histopathological analyses. One hundred and seven samples (92%) contained CMV DNA and 66/116 (57%) contained HIV proviral DNA at a level of > or = 10 genomes. Both viruses were detected in 60/116 (51.7%) of samples, with co-infection most frequent in the lung (69%). Cell culture for CMV detected 9.3% of the PCR-positive samples, whilst histology identified CMV inclusions in 15.9% of samples, all of which were CMV PCR-positive. CMV was most frequently detected in adrenal and lung tissues by histology. These results show that co-infection with CMV and HIV is a common occurrence in organs from AIDS patients and provide further evidence for a role of cytomegalovirus in the pathogenesis of AIDS.

Influence of electrical stimulation of the tibialis anterior muscle in paraplegic subjects. 2. Morphological and histochemical properties

In adult paraplegic subjects one tibialis anterior muscle received daily electrical stimulation for 4 weeks at twice the motor threshold to determine changes of morphological and histochemical profiles (this paper) and of contractile properties (preceding paper). Bilateral biopsies, obtained 4 weeks before, and immediately after, electrical stimulation, were studied for fibre type proportions, fibre diameters, oxidative capacity, microvasculature and histopathology. Before stimulation the biopsies showed disuse with increased type 2 fibre proportions and decreased oxidative capacity (succinate dehydrogenase (SDH) activity). The effects of two stimulus patterns were compared. Following stimulation SDH activity increased significantly in all stimulated muscles. Inconsistent changes occurred in fibre type proportions, fibre diameters, capillary density and capillary/fibre ratios. Both stimulus patterns evoked similar results. In five/seven subjects subsarcolemmal vacuolation was observed. Electrical stimulation for 4 weeks at only twice motor threshold improves oxidative capacity, but different stimulus parameters are probably needed for significant fibre type conversion.

Influence of electrical stimulation of the tibialis anterior muscle in paraplegic subjects. 1. Contractile properties

In adult paraplegic subjects one tibialis anterior muscle received daily electrical stimulation for 4 weeks at twice motor threshold to determine changes of its contractile properties (this paper) and its morphological and histochemical profiles (following paper). Force, speed of contraction and fatigue resistance were assessed by percutaneous electrical stimulation of the muscle with torque measured about the ankle. Comparative contractile tests were performed on 51 normal adult subjects and new parameters for force measurement proposed, particularly where maximum voluntary contraction cannot be obtained. In paraplegic subjects before stimulation the tibialis anterior muscle showed evidence of disuse with decreased force, faster contraction and relaxation, and reduced fatigue resistance. The effects of two stimulus patterns were compared: 10 Hz, and 10 Hz with 100 Hz bursts. After stimulation contraction was slower, fatigue resistance increased and there was a tendency for force to increase. No differences occurred using the different stimulus patterns. Four weeks later fatigue resistance was partially maintained, while speed of contraction reverted to pre-stimulus levels.

Modelling the relative metabolic occurrence of alkyl-nitrogen bond cleavage using structure-reactivity maps

Over a broad range of tertiary N-methyl amines, whenever alkyl-nitrogen bond cleavage was observed, N-demethylation was also observed. Alkyl-nitrogen bond cleavage in rings, alkyl-nitrogen bond cleavage if the carbon of the N-dealkylation reaction-site is in a ring and the nitrogen atom of the reaction-site is not in a ring, and dedimethylamination are not likely to occur relative to N-demethylation. Structure-reactivity relationships for other N-dealkylations, such as N-debenzylation, N-dethiophenation, and N-dedimethylaminoethylation of tertiary amines were evident from a visual inspection of the structure-reactivity map. Structure-reactivity maps proved to be a useful tool for ascertaining structural environments influencing the relative occurrence of alkyl-nitrogen bond cleavage in tertiary N-methyl amines.

Changes to alveolar macrophage phenotype in HIV infected individuals with normal CD4 counts and no respiratory disease

BACKGROUND

It has previously been shown that HIV infected individuals with pneumonitis have identifiable abnormalities in alveolar macrophages obtained by bronchoalveolar lavage (BAL). In particular, alterations in the expression of alveolar macrophage surface antigens associated with macrophage function have been reported. To determine whether these changes reflect HIV infection or the respiratory episode itself, a population of HIV infected patients with no respiratory disease was studied.

METHODS

Twenty two HIV antibody positive individuals with a peripheral blood CD4 count of > 400/microliters and 10 healthy volunteer controls underwent bronchoscopy and BAL. Cytospin preparations from the recovered cells were stained using immunoperoxidase and double immunofluorescence techniques with monoclonal antibodies RFD1, RFD7, EBM11/CD68 (mature macrophages), UCHM1/CD14 (monocyte marker), and HLA-DR (RFDR1). Differential cell counts were also performed.

RESULTS

There was an increase in overall alveolar macrophage HLA-DR expression in the HIV population. This was not reflected in a change in the percentage of cells staining CD14 (monocytes) or CD68 (mature macrophages) positive. The relative proportions of cells staining RFD1 + RFD7- (inducer cells), RFD1 - RFD7+ (effector cells), and RFD1 + RFD7+ (suppressive cells) were unchanged between HIV and control groups.

CONCLUSIONS

In a population of HIV infected individuals with normal CD4 counts and no respiratory disease there was an increase in overall alveolar macrophage HLA-DR expression which occurred independently of any alteration in the relative proportions of alveolar macrophage subpopulations.

Staging system for clinical AIDS patients. Royal Free/Chelsea and Westminster Hospitals Collaborative Group

Although there are wide differences in prognosis between patients with AIDS they are often thought of as a single homogeneous group. We think a simple staging system that accounts for important prognostic factors including type and number of AIDS diseases and the CD4 lymphocyte count is required. We followed 363 AIDS patients at the Royal Free Hospital and reported the occurrence of 680 AIDS-defining diseases (ADDs). We measured CD4 counts at approximately monthly intervals. Severity of AIDS diseases was defined a priori on the basis of survival in the AIDS in Europe study of 6578 AIDS patients: mild-oesophageal candidiasis, Kaposis sarcoma (cutaneous), Pneumocystis carinii pneumonia, extrapulmonary tuberculosis; severe-all other ADDs except lymphoma; very severe-lymphoma. The risk of death increased by 15% (p = 0.08) for each mild condition experienced, by 89% (p < 0.0001) for each new severe condition and by 535% (p < 0.0001) when a lymphoma developed. Estimates from the Cox model were used to derive a score reflecting the risk of death. Patient experience was divided into three categories. Patients in AIDS Grade I had an average death rate of one per 10.1 years, compared with one per 2.8 years in AIDS Grade II and one per 1.1 years in AIDS Grade III. Similar rates were seen in an independent validation study on 1230 AIDS patients at different hospital. Our grading system should be useful for patient management, clinical trial design, surveillance, and resource management.

Distinct HIV-1 long terminal repeat quasispecies present in nervous tissues compared to that in lung, blood and lymphoid tissues of an AIDS patient

OBJECTIVE

To investigate the phylogenetic relationship of HIV-1 proviral long terminal repeat (LTR) variants present in postmortem samples of lymph node, spleen, lung, dorsal root ganglion and spinal cord as well as in the peripheral blood of an HIV-1-infected patient dying with AIDS.

DESIGN AND METHODS

Postmortem tissues were studied by a combination of histology, cell culture and molecular analyses. The patient had a stable CD4 count of 10 x 10(6)/I during the 12 months preceding death. A 540 base-pair fragment of the LTR including U3/R/U5 was amplified using polymerase chain reaction on proviral DNA from the five postmortem tissues and peripheral blood mononuclear cells obtained 2 months prior to death. The population of viral variants was determined by sequencing at least five plasmid clones of the amplicons. The relationship between the variants present in different body sites was investigated using molecular phylogeny methods.

RESULTS

HIV-1 was present in all organs analysed and correlated with the presence of abnormal histology. Genetic variation leading to divergence from the consensus sequence was more frequently present in characterized transcription factor binding sites within the LTR (P < 0.0001) although the HIV-1 LTR quasispecies in the different body sites showed similar, relatively low levels of divergence (intra-organ median heterogeneity ranging from 0.0094 to 0.017). Phylogenetic analysis showed that the spinal cord and dorsal root ganglion harboured an LTR population genetically distinct from that present in other organs and more closely related to a previously characterized neurotropic strain of HIV (strain JRcsf).

CONCLUSION

The independent clustering of HIV-1 LTR variants present in spinal cord and dorsal root ganglion shows that HIV-1 LTR evolution can occur in a compartmentalized fashion. The data show that the LTR is an important region to analyse in sequence variation studies of HIV since it may play a role in nervous tissue adaptation of HIV-1 and neuropathogenicity. Outgrowth of HIV-1 LTR variants that are most fit for the utilization of tissue-specific transcription factors can occur in the nervous tissue.

Edhazardia aedis (Microspora: Culicosporidae) effects on the reproductive capacity of Aedes aegypti (Diptera: Culicidae)

The influence of the microsporidium Edhazardia aedis (Kudo) on the survival and reproduction of its mosquito host, Aedes aegypti (L.), was studied in the laboratory. Survival, fecundity, egg hatch, and percentage of emergence for 4 gonotrophic cycles were compared for control and infected mosquitoes. Control females oviposited an average of 123.1 eggs over 4 gonotrophic cycles, 86.1% of which hatched, whereas infected females laid an average of 38.0 eggs with a 69.3% hatch. Emergence in progeny of infected female Ae. aegypti was significantly less than for control mosquitoes in all gonotrophic cycles. The reproductive capacity (Ro) for control and infected adults was 168.4 and 4.1, respectively, representing a decrease of 98.2%. Overall infection levels in progeny of infected females was 95.7%, of which 46.6% were lethal, larval infections. Infected female survivors were capable of initiating infections in F2 progeny. Wing length, often used as an indicator of fitness, was not significantly different between infected and control adults.

Presence of CD3+CD8+Bcl-2(low) lymphocytes undergoing apoptosis and activated macrophages in lymph nodes of HIV-1+ patients

Infection with human immunodeficiency virus 1 causes profound changes in the lymph nodes of infected patients. In particular, large numbers of CD8+CD45RO+ T cells infiltrate both the paracortex and the germinal centers. These cells contained the cytotoxic granule-associated protein TIA-1 but showed no detectable levels of perforin and shared the same characteristics of the expanded, activated, short-lived CD8+ population found during acute viral infections. These cells expressed low levels of Bcl-2 and are likely to be short-lived in vivo as evidenced by the direct observation of CD8+ apoptotic cells in the paracortical areas of the infected nodes. Changes in the paracortical nonlymphoid populations were also seen. There were reactive changes in the blood vessels, and the macrophage population was expanded and activated. Furthermore, apoptotic bodies were seen in the cytoplasm of the activated CD68+RFD-7+RFD-1+ macrophages pointing to the phagocytic capacity of these cells and their role in the clearance of the apoptotic cells from the tissues. These observations suggest that the persistance of CD8+ population in human immunodeficiency virus 1 infection is not a result of the presence of an abnormal CD8+ population but rather a result of an inappropriate over-stimulation of the CD8+ cells.

Docosahexaenoic acid-induced alteration of Thy-1 and CD8 expression on murine splenocytes

Here we test whether the incorporation of docosahexaenoic acid (DHA, 22:6), an (n-3) fatty acid, into lymphocyte membranes affects the expression of the surface proteins Thy-1.2 and CD8. DHA was incorporated into splenocytes by three methods: feeding mice diets containing menhaden (fish) oil, fusing splenocytes with DHA-containing phosphatidylcholine vesicles, and culturing splenocytes with DHA. Thy-1.2 and CD8 expression were measured by flow cytometry and complement-mediated lysis using a panel of monoclonal antibodies. As (n-3) fatty acid incorporation into the lymphocytes increased, the expression of one Thy-1.2 epitope and one CD8 epitope decreased; the expression of two CD8 epitopes increased. Although diet-induced changes in surface protein expression may result from selective migration of cell populations or the diet's effect on protein biosynthesis, fusion with lipid vesicles demonstrated that DHA-containing phospholipids can mediate a direct and immediate effect. The decrease in Thy-1.2 expression was sustained for more than a week after removal of (n-3) fatty acids from the diet, most likely due to retention of membrane-bound (n-3) fatty acids. Because Thy-1.2 and CD8 participate in T cell activation, modulation of their expression by DHA suggests that DHA, when serving as a membrane structural element, may alter immune function.

Antagonism of the effects of clonidine by the alpha 2-adrenoceptor antagonist, fluparoxan

1. The effects of fluparoxan, an alpha 2-adrenoceptor antagonist, on the pharmacodynamic changes induced by clonidine were investigated in this placebo-controlled, double-blind, two-period, cross-over study in 16 healthy male volunteers (aged 19 to 44 years). 2. Subjects received either fluparoxan or placebo, twice-daily for 5 1/2 days (11 doses). One hour after the first and last dose of each treatment period, clonidine (200 micrograms) was infused intravenously over 5 min. 3. Indices of clonidine-mediated pharmacodynamic responses (growth hormone secretion, bradycardia, hypotension, xerostomia and sedation) were taken before and after clonidine infusion. Growth hormone secretion was assessed by quantifying serum growth hormone concentrations; sedation was assessed by both visual analogue scales (VAS) and by a visual psychomotor response meter, measuring critical flicker fusion (CFF). 4. The majority of subjects reported minor adverse events such as lethargy, headache and dry mouth following clonidine infusion. All adverse events were likely to be related to clonidine, as they occurred consistently between treatment groups. Fluparoxan has, however, in previous studies been reported to cause headache and light-headedness. 5. Prior to the clonidine infusion, fluparoxan caused small but statistically significant increases in systolic blood pressure (4 mm Hg) and salivary flow (approximately 30%) after both single and repeated doses. A small increase in heart rate (2 beats min-1) was seen after a single dose which was also statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Extra-adrenal pheochromocytoma in pregnancy: ultrasonography and magnetic resonance imaging findings

The authors describe a 24-year-old woman with extra-adrenal pheochromocytoma during pregnancy. Initial ultrasonography (US) at 27 weeks gestational age failed to show the pheochromocytoma, which was subsequently found by US at 35 weeks gestational age. Magnetic resonance imaging (MRI) provided diagnostic confirmation, as well as important information used by the obstetrician and the surgeon in operative planning.

Presentation and clinical investigation of mitochondrial respiratory chain disease. A study of 51 patients

Defects of the mitochondrial respiratory chain are associated with a great variety of clinical disorders. Whilst recognition of these conditions is increasing, the need for sophisticated biochemical and molecular studies has tended to limit both their investigation and diagnosis to a few specialist centres. Using a group of 51 patients with histochemically, biochemically and/or genetically defined respiratory chain defects, we have examined both the clinical heterogeneity of these disorders and how they may be investigated most effectively in non-specialist centres. We evaluated the use of the following routinely available clinical investigations--fasting intermediary metabolites (lactate, pyruvate, ketone bodies, etc.) in blood and cerebrospinal fluid, serum creatine kinase estimation, EMG, EEG, CT, MRI and histological/histochemical muscle biopsy analysis. Our studies show that, in addition to well-recognized syndromes (e.g. chronic progressive external ophthalmoplegia, mitochondrial encephalopathy lactic acidosis and stroke like episodes, and myoclonus epilepsy with ragged red-fibres, a significant number of patients present with non-specific encephalopathic disorders. Furthermore, even within those categories of respiratory chain disease which have been genetically defined, a wide variation of presenting symptoms and signs were found. Where there was initial doubt concerning the diagnosis, the following clinical features were helpful in suggesting respiratory chain disease: ophthalmoplegia; a maternal pattern of inheritance; the presence of myopathy or deafness in association with encephalopathy. Of the clinical investigations we assessed, elevated lactate in blood or cerebrospinal fluid and low density lesions in the basal ganglia were helpful in identifying patients with respiratory chain dysfunction. Histochemical analysis of muscle was, however, the single most useful investigation being diagnostic in patients with chronic progressive external ophthalmoplegia, Kearns-Sayre syndrome and myopathy, and of significant importance in patients presenting primarily with central nervous system disease. The results of our study are used to discuss the most appropriate approach to diagnosis of this group of disorders.

ICP27 immediate early gene, glycoprotein K (gK) and DNA helicase homologues of infectious laryngotracheitis virus (gallid herpesvirus 1) SA-2 strain

A 4.8 kilobase segment located at the left-terminal in the unique long (UL) region of infectious laryngotracheitis virus (ILTV) SA-2 strain contained three open reading frames (ORFs). The first of 421 amino acids (aa) was located at map units 0.065 to 0.07, and its predicted 48 kiloDaltons (kDa) protein product has significant homology to the immediate early regulatory protein ICP27 (UL54) of herpes simplex virus type-1 (HSV-1), to varicella-zoster virus (VZV) ORF4 and to equine herpesvirus 1 (EHV-1) ORF5. The zinc finger conserved in the C-terminal of the proteins from HSV-1, VZV and EHV-1, is poorly conserved in ILTV homologue. The second ORF of 336 aa, located at map units 0.075 to 0.08, has a predicted molecular weight (MW) of 38 kDa with significant homology to glycoprotein K (gK) of HSV-1 (UL53), ORF5 of VZV and ORF6 of EHV-1. ILTV gK has features characteristic of a membrane-bound glycoprotein. The 3' region of a third ORF was located at map units 0.08 to 0.095. Translation of the sequence revealed significant homology to the 3'-region of the DNA helicase-primase complex protein (UL52) of HSV-1, ORF6 of VZV and ORF 7 of EHV-1. Northern blot analyses were used to characterize the ILTV ICP27, gK and DNA helicase mRNAs. The data revealed that ILTV ICP27 is an immediate early gene that encodes a 1.6 kb mRNA, ILTV gK encodes a late transcript of 1.8 kb, while ILTV DNA helicase encodes a late transcript of 3.7 kb.

Intestinal disaccharidase activity in human immunodeficiency virus disease

BACKGROUND

The relationship between disaccharidase activity, progression of human immunodeficiency virus (HIV) disease, and diarrhoea and weight loss was investigated.

METHODS

Forty-six HIV-positive patients ingested a solution of lactose, palatinose, sucrose, and lactulose after 24 h of dietary exclusion and overnight fasting, after which urine was collected for 10 h. Urinary disaccharide (activity) ratios-lactose/lactulose (L/LL), palatinose/lactulose (P/LL), and sucrose/lactulose (S/LL)-were measured by thin-layer chromatography.

RESULTS

There was a significant decrease in disaccharidase activity (L/LL, P/LL, and S/LL) with advancing clinical stage of HIV disease (p < 0.05, Wilcoxon rank sum test) as well as decreasing CD4 count (p < 0.05, Spearman correlation). Patients with weight loss/diarrhoea also had significantly (p < 0.05) decreased disaccharidase activity compared with control but not as compared with AIDS patients. Anti-retroviral therapy did not influence disaccharidase activity.

CONCLUSION

Impairment of disaccharidase activity occurs with advancing HIV disease, but its role in HIV patients with weight loss and diarrhoea remains to be determined.

Nucleotide sequence of infectious laryngotracheitis virus (gallid herpesvirus 1) ICP4 gene

The infectious laryngotracheitis virus (ILTV) gene encoding a homologue to the ICP4 protein of herpes simplex virus (HSV) has been mapped to the inverted repeat region. The complete nucleotide sequence of ILTV ICP4 has been determined. The ILTV ORF encoding ICP4 is 4386 nucleotides long, calculated from the first of four ATG codons, and has an overall G+C content of 59%. The ILTV ICP4 contains two domains of high homology which have been reported in other studies to be conserved in the ICP4 homologues of alphaherpesviruses, and to be functionally important. Several regulatory features were identified including a serine-rich domain in region one. A more extensive serine-rich domain was located in region five which is also found in varicella-zoster virus (VZV) and bovine herpesvirus 1. A 5.4 kb immediate early transcript was identified in infected primary kidney cells.

Nucleotide sequence analysis of an infectious laryngotracheitis virus gene corresponding to the US3 of HSV-1 and a unique gene encoding a 67 kDa protein

The DNA sequence of 4005 nucleotides from the Kpnl O and part of Kpnl K fragments in the short unique region of infectious laryngotracheitis virus (ILTV) was determined. The sequence contained two complete and one partial open reading frames (ORFs). The partial ORF was open at the 5' end of the sequence and represented the NH2-terminal 118 amino acids (aa) of a polypeptide. Its partial predicted protein product exhibited significant homology to the US2 gene product of HSV-1 (herpes simplex virus type 1) and it homologs in other herpesviruses. ORF 2 is 471 aa long and could encode a protein of 53.8 kDa which shared aa homology with the protein kinases encoded by HSV-1 US3 and its gene homologs. Analysis of the ORF 2 aa sequence revealed domains characteristic of protein-serine/threonine (S/T) kinases of cellular and viral origin. The ORF 3 encoded a predicted protein of 601 aa (M(r) 67.5 kDa) which exhibited limited homology (18% overall identity) with the UL47 protein (major tegument protein) of HSV-1. Northern (RNA) blot hybridization and metabolic inhibitors were used to characterize the ILTV protein kinase and the 67K mRNAs. The data revealed that protein kinase is a gamma-1 gene encoding a 1.6 mRNa, while the 67K ORF is a gamma-2 gene encoding a 2 kb mRNA.

Sequence characteristics of a gene in infectious laryngotracheitis virus homologous to glycoprotein D of herpes simplex virus

An infectious laryngotracheitis virus (ILTV, gallid herpesvirus 1) gene homologous to glycoprotein D of herpes simplex virus (HSV) was identified and characterized by its nucleotide and derived amino acid sequence. The ILTV gD gene is located in the unique short region (U(s)) and contains an open reading frame capable of specifying a polypeptide of 380 amino acids, including N- and C- terminal hydrophobic domains consistent with signal and anchor regions respectively, and no potential sites for N-glycosylation. Alignment of the amino acid sequence with those published for HSV gD, equine herpesvirus type 1 (EHV-1) gD, pseudorabies virus (PRV) gp50, Marek's disease virus (MDV) gD, herpesvirus of turkeys (HVT) gD and bovine herpesvirus type 1 (BHV-1) gD showed similarities over the N-terminal region, with the greatest differences occurring in the C-terminal. The identical positioning of 6 cysteine residues supports the hypothesis of common ancestry of herpesvirus family (McGeoch, 1990) and is consistent with the essential role of this glycoprotein.