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PubMed2006

Plasmid pBP136 from Bordetella pertussis represents an ancestral form of IncP-1beta plasmids without accessory mobile elements.

The complete 41,268 bp nucleotide sequence of the IncP-1beta plasmid pBP136 from the human pathogen Bordetella pertussis, the primary aetiological agent of whooping cough, was determined and analysed. This plasmid carried a total of 46 ORFs: 44 ORFs corresponding to the genes in the conserved IncP-1beta backbone, and 2 ORFs similar to the XF1596 and XF1597 genes with unknown function of the plant pathogen Xylella fastidiosa. Interestingly, pBP136 had no accessory genes carrying genetic traits such as antibiotic or mercury resistance and/or xenobiotic degradation. Moreover, pBP136 had only two of the kle genes (kleAE) that have been reported to be important for the stability of IncP-1 plasmid in Pseudomonas aeruginosa. Phylogenetic analysis of the Kle proteins revealed that the KleA and KleE of pBP136 were phylogenetically distant from those of the present IncP-1 plasmids. In contrast, IncC1 and KorC, encoded upstream and downstream of the kle genes respectively, and the replication-initiation protein, TrfA, were closely related to those of the IncP-1beta 'R751 group'. These results suggest that (i) pBP136 without any apparent accessory genes diverged early from an ancestor of the present IncP-1beta plasmids, especially those of the R751 group, and (ii) the kle genes might be incorporated independently into the backbone region of the IncP-1 plasmids for their stable maintenance in various host cells.

Bacterial Proteins↗
PubMed1989

Sequence of the nagBACD operon in Escherichia coli K12 and pattern of transcription within the nag regulon.

The DNA sequence of a 3.6kb region downstream of the nagB gene (encoding glucosamine-6-PO4-deaminase) in Escherichia coli has been determined. Three open reading frames, which are subsequently referred to as nagA, nagC and nagD, were detected in this sequence. Genetic complementation and enzyme assays have shown that the first of these, nagA, encodes N-acetyl glucosamine-6-phosphate deacetylase. Growth on N-acetyl glucosamine induces the synthesis of a 1900 nucleotide long transcript which covers just nagE, encoding EIINag which is transcribed divergently from nagB, and of a 4200 nucleotide long transcript which covers all four ORFs of the nagB,A,C, D operon. More mRNA corresponding to nagB and nagA is detected than that corresponding to the distal genes, nagC and nagD. Considerable amounts of the induced mRNA are truncated molecules having their 3' ends after nagB and after nagA. Multiple 3' RNA ends have been mapped after nagD and seem to correspond to the ends of transcripts stabilized by mRNA secondary structure (REP sequences) rather than transcription termination sites. A second promoter producing nagD-specific transcripts has been mapped just in front of the nagD gene.

Acetylglucosamine↗
PubMed1999

The mithramycin gene cluster of Streptomyces argillaceus contains a positive regulatory gene and two repeated DNA sequences that are located at both ends of the cluster.

Sequencing of a 4.3-kb DNA region from the chromosome of Streptomyces argillaceus, a mithramycin producer, revealed the presence of two open reading frames (ORFs). The first one (orfA) codes for a protein that resembles several transport proteins. The second one (mtmR) codes for a protein similar to positive regulators involved in antibiotic biosynthesis (DnrI, SnoA, ActII-orf4, CcaR, and RedD) belonging to the Streptomyces antibiotic regulatory protein (SARP) family. Both ORFs are separated by a 1.9-kb, apparently noncoding region. Replacement of the mtmR region by an antibiotic resistance cassette completely abolished mithramycin biosynthesis. Expression of mtmR in a high-copy-number vector in S. argillaceus caused a 16-fold increase in mithramycin production. The mtmR gene restored actinorhodin production in Streptomyces coelicolor JF1 mutant, in which the actinorhodin-specific activator ActII-orf4 is inactive, and also stimulated actinorhodin production by Streptomyces lividans TK21. A 241-bp region located 1.9 kb upstream of mtmR was found to be repeated approximately 50 kb downstream of mtmR at the other end of the mithramycin gene cluster. A model to explain a possible route for the acquisition of the mithramycin gene cluster by S. argillaceus is proposed.

Amino Acid Sequence↗
PubMed2002

Genetic analysis of the basis of translation in the -1 frame of an unusual non-ORF sequence isolated from phage display.

An unusual peptide-encoding sequence, called H10, and several derivatives of this sequence were previously isolated from a random peptide library screened by phage display during drug discovery protocols. The H10 family of sequences had the unusual property of being expressed despite the absence of an open reading frame. When these sequences were fused to a reporter lacZ gene in all three frames, beta-galactosidase was expressed not only from the parental non-open reading frame, consistent with the original isolations, but also from the frame -1 to the parental. This unexpected translation in a second reading frame could result from either a recoding event or from an internal translation initiation event. In order to elucidate which type of event, a genetic approach was selected to eliminate a potential downstream initiator site within the H10 sequence. This report provides strong evidence that translation in the -1 frame in this family of sequences is indeed originating from a downstream translation initiation event. Unexpectedly, the mutation eliminating the downstream initiation event in the -1 frame simultaneously elevated expression in the original non-open reading frame.

Amino Acid Sequence↗
PubMed1993

DNA sequence and transcriptional analyses of the region of the equine herpesvirus type 1 Kentucky A strain genome encoding glycoprotein C.

DNA sequence and transcriptional analyses were performed on the region of the equine herpesvirus type 1 (EHV-1) genome (KyA strain) (map units 0.129 to 0.152) encoding open reading frames (ORFs) 15 and 16. ORF16 encodes a homolog of glycoprotein C of HSV-1 (herpes simplex virus type 1), while ORF15 corresponds in position to HSV-1 UL45 but exhibits no significant homology at the amino acid level. Sequence analyses revealed that the EHV-1 gC ORF of 468 amino acids and ORF15 of 227 amino acids mapped at nucleotides (nt) 716 to 2119 and 2397 to 3077, respectively (relative to the 5' end of the BamHI recognition site at map unit 0.152). ORF15 exhibited significant homology (69% identity) at the amino acid level to the EHV-4 gene located 3' of the EHV-4 gC homolog. Sequence analyses identified potential CAAT and TATA boxes for the EHV-1 gC ORF and a TATA box for ORF15. While no consensus polyadenylation signal was detected between ORFs 15 and 16, two polyadenylation signals were detected 3' of ORF15. Northern blot and S1 nuclease analyses were used to map and characterize the gC and ORF15 mRNAs, and metabolic inhibitors were used to identify the kinetic class of these two genes. The results revealed that gC is a gamma-1 gene which encodes a 2.8-kb mRNA, while ORF15 is a gamma-2 gene encoding a 0.9-kb mRNA which is 3' coterminal with the gC transcript. The gC and ORF15 mRNAs were shown by S1 nuclease analyses to initiate approximately 34 and 26 nucleotides downstream of their respective TATA boxes and to have a common termination site 18 to 20 nucleotides downstream of a consensus polyadenylation signal. Comparative sequence analysis revealed that the KyA strain gC protein differs in only three amino acid residues from the gC protein of the EHV-1 Ab4 and T431 strains, and one of the three amino acid differences occurred within a segment of six contiguous amino acids showing high degree of hydrophilicity in the gC molecule. Further comparative sequence analysis revealed that KyA strain genome has a major deletion in the region of ORF17 which lies 5' of gC in the Ab4 strain. This finding that 1038 base pairs (bp) of the 1203-bp ORF17 is deleted indicates that ORF17 is nonessential for EHV-1 replication in cell culture. To examine the regulation of the EHV-1 gC gene, transient transfection assays using CAT (chloramphenicol acetyltransferase) reporter gene constructs of gC were performed.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1993

Cloning and molecular analysis of the poly(3-hydroxybutyric acid) biosynthetic genes of Thiocystis violacea.

From a genomic library of Thiocystis violaceae strain 2311 in lambda L47, two adjacent EcoRI restriction fragments of 5361 base pairs (bp) and of 1978 bp were cloned. The 5361-bp EcoRI restriction fragment hybridized with a DNA fragment harbouring the Alcaligenes eutrophus poly(3-hydroxyalkanoate) (PHA) synthase operon (phbCAB) and restored the ability to synthesize and accumulate PHA in PHA-negative mutants derived from A. eutrophus. The nucleotide sequence analysis of both fragments revealed five open-reading frames (ORFs); at least three of them are probably relevant for PHA biosynthesis. The amino acid sequences of the putative proteins deduced from these genes indicate that they encode a beta-ketothiolase [phbATv, relative molecular mass (M(r)) 40850], which exhibited 87.3% amino acid identity with the beta-ketothiolase from Chromatium vinosum. The amino acid sequences of the putative proteins deduced from ORF2Tv (M(r) 41450) and phbCTv (M(r) 39550), which were located upstream of and antilinear to phbATv, exhibited 74.7% and 87.6% amino acid identity, respectively, with the corresponding gene products of C. vinosum. Downstream of and antilinear to phbCTv was located ORF5, which encodes for a protein of high relative molecular mass (M(r) 76428) of unknown function. With respect to the divergent organisation of ORF2Tv and phbCTv on one side and of phbATv on the other side and from the homologies of the putative gene products, this region of the T. violaceae genome resembled very much the corresponding region of C. vinosum, which was identified recently.

Amino Acid Sequence↗
PubMed2006

Novel transcript nort is a downstream target gene of the Notch signaling pathway in zebrafish.

The Notch signaling pathway plays important roles in the regulation of diverse developmental processes. Although many Notch-signal target genes with different specificities have been identified, their regulation and functions are not fully understood. Here, we conducted a microarray screen to search for novel downstream target genes of the Notch pathway in zebrafish. From the screen, we isolated nort (Notch-regulated transcript) as a transcript whose expression was reduced by the inhibition of Notch signaling. The expression level of nort increased when Notch signaling was activated. nort was expressed in hypoblast cells and the developing nervous system. We found its expression pattern to be similar to that of her4, but it showed some differences, at least in the anterior and posterior neural plate at the 3-somite stage. The nort transcript did not contain any long open-reading frame (ORF) of more than 300 nt, and its ORF-encoded sequence showed no significant homology with the proteins in databases. However, nort has one SPS (suppressor of hairless paired binding site) in its 5'-flanking region. These data suggest that nort is a putative noncoding RNA regulated by Notch signaling.

5' Flanking Region↗
PubMed2002

Intron-dependent stimulation of marker gene expression in cultured insect cells.

We tested in a systematic fashion the effect of an intron on the level of luciferase expression in cultured C6/36 Aedes albopictus cells. The intron was inserted in both orientations, upstream and downstream of the luciferase coding region in two different luciferase expression vectors. The two parental luciferase expression vectors differed only in their promoters, one containing the Drosophila melanogaster actin5C promoter and the other the Autographa californica nuclear polyhedrosis virus hr5/ie1 enhancer/promoter. All resulting intron-containing constructs were tested for their ability to express luciferase in transient assays following electroporation into C6/36 cells. We found that the introns stimulate luciferase expression between twelve and sixtyfold, depending on the promoter. Enhanced expression was only seen when the intron was present in the correct orientation upstream of the luciferase ORF. When the 3' splice sites of the enhanced intron-containing constructs were mutated, the expression level dropped back to below the level of the intronless parental constructs, suggesting that the intron-dependent stimulation of luciferase expression is depending on splicing and is not due to other effects the intron may have on transcription or translation. The luciferase transcripts of all constructs were analysed by reverse transcription, PCR amplification and sequencing, and the results show a perfect correlation between efficient splicing of the intron and elevated levels of luciferase expression. Our findings have the potential to be very useful for boosting expression of foreign proteins in the widely used baculoviral or non-viral systems in insect cells.

Aedes↗
PubMed1994

Chimeric transcripts with an open reading frame are generated as a result of translocation to the Pvt-1 region in mouse B-cell tumors.

Some mouse plasmacytomas exhibit a t(6;15) chromosomal translocation in which the breakpoint resides within the Pvt-1 locus located 260 kilobases (kb) downstream of c-myc on mouse chromosome 15. In this report, we show that the Pvt-1 locus does not exhibit allelic exclusion in that Pvt-1 transcripts continue to be expressed from the non-translocated allele in t(6;15) plasmacytomas. From the translocated allele, we find chimeric transcripts containing a short 57-bp segment of Pvt-1 (termed Pvt-1a) spliced directly to the immunoglobulin constant region sequence (Ig-Ck). These short transcripts have replaced a Jk segment with a trytophan residue via RNA splicing and contain a continuous open reading frame (ORF) from Pvt-1a through Ck. Since this Pvt-1a/Ck transcript is found in all 3 t(6;15) plasmacytomas examined, regardless of the location of the chromosomal breakpoint, we suggest that the Pvt-1a/Ck chimera may have a functional role in the development of mouse plasmacytomas.

Amino Acid Sequence↗
PubMed1995

Dissection of the core and auxiliary sequences in the vegetative replication origin of promiscuous plasmid RK2.

The vegetative replication origin (oriV) of promiscuous IncP plasmid RK2 can function in many Gram-negative bacterial species when supplied with the plasmid-encoded replication protein TrfA and host-encoded replication proteins including DnaA. Nine TrfA binding sites (iterons) are known, and also two DnaA binding sites, box 1, between TrfA iterons 4 and 5, and box 2, downstream of repeat 9. The deletion analysis presented here shows that the core oriV requires DnaA box 1 for function in Escherichia coli and Pseudomonas putida. This DnA box is not essential in Pseudomonas aeruginosa, although its deletion does reduce plasmid copy number in this species. A putative IHF binding site is located upstream of DnaA box 1, but IHF deficiency in E. coli seems not to alter replication efficiency or copy number control. Cloned oriV can interfere with maintenance of an independent RK2 replicon. Analysis of replication inhibition functions associated with oriV showed that a short putative orf between TrfA iterons 1 and 2 is not necessary for replication inhibition, the presence of repeats 5 to 9 in target and inhibitor plasmid are not sufficient for efficient inhibition and inhibition does not correlate directly with the number of direct repeats present. Rather, the results showed that the isolated repeats 1 and 2 to 4, potentiate replication inhibition disproportionately to their effect on the number of TrfA binding sites. The results are consistent with the idea that repeats 1 to 4, arranged as a single copy and as an irregular group of three, potentiate the ability of the oriV region to form complexes which inhibit replication. We suggest that TrfA bound at these iterons may be more susceptible to forming pairs between oriV sequences on different plasmids.

Bacterial Proteins↗
PubMed1991

The translation in vitro of rat ornithine decarboxylase mRNA is blocked by its 5' untranslated region in a polyamine-independent way.

The enzyme ornithine decarboxylase (ODC, EC 4.1.1.17) is believed to play an essential role in the growth and differentiation of cells by regulating the biosynthesis of polyamines. The 5' untranslated region (5' UTR) of the ODC mRNA of different species is rather unusual in length and GC content, and may therefore be involved in translational control of ODC protein synthesis. We cloned the rat ODC cDNA downstream of the phage T7 promoter in order to perform transcription/translation studies in vitro. Our results show that the intact 5' UTR of rat ODC mRNA, which is 303 nt in length, is a potent inhibitor of translation. Efficient synthesis in vitro of ODC protein is obtained when either 172 nt from the 5'-end or 236 nt from the 3'-end of the 5' UTR are removed. A truncated 5' UTR with a calculated free energy of less than -272 kJ (-65 kcal/mol) is unable to support the synthesis in vitro of ODC protein. The short open reading frame (ORF) present in the 5' UTR of rat ODC mRNA does not contribute to the observed inhibitory effect on translation efficiency in vitro. At low polyamine concentration the efficiency of translation in vitro of intact ODC mRNA is not relatively increased compared with that of an ODC mRNA having a truncated 5' UTR or with that of control globin mRNA. From this we conclude that the well-documented negative feedback control of intracellular polyamines on ODC expression is not regulated by effects of polyamines on the secondary structure of the 5' UTR of ODC mRNA.

Amino Acid Sequence↗
PubMed2000

The Pseudomonas syringae Hrp pathogenicity island has a tripartite mosaic structure composed of a cluster of type III secretion genes bounded by exchangeable effector and conserved effector loci that contribute to parasitic fitness and pathogenicity in plants.

The plant pathogenic bacterium Pseudomonas syringae is divided into pathovars differing in host specificity, with P. syringae pv. syringae (Psy) and P. syringae pv. tomato (Pto) representing particularly divergent pathovars. P. syringae hrp/hrc genes encode a type III protein secretion system that appears to translocate Avr and Hop effector proteins into plant cells. DNA sequence analysis of the hrp/hrc regions in Psy 61, Psy B728a, and Pto DC3000 has revealed a Hrp pathogenicity island (Pai) with a tripartite mosaic structure. The hrp/hrc gene cluster is conserved in all three strains and is flanked by a unique exchangeable effector locus (EEL) and a conserved effector locus (CEL). The EELs begin 3 nt downstream of the stop codon of hrpK and end, after 2.5-7.3 kb of dissimilar intervening DNA with tRNA(Leu)-queA-tgt sequences that are also found in Pseudomonas aeruginosa but without linkage to any Hrp Pai sequences. The EELs encode diverse putative effectors, including HopPsyA (HrmA) in Psy 61 and proteins similar to AvrPphE and the AvrB/AvrC/AvrPphC and AvrBsT/AvrRxv/YopJ protein families in Psy B728a. The EELs also contain mobile genetic element sequences and have a G + C content significantly lower than the rest of the Hrp Pai or the P. syringae genome. The CEL carries at least seven ORFs that are conserved between Psy B728a and Pto DC3000. Deletion of the Pto DC3000 EEL slightly reduces bacterial growth in tomato, whereas deletion of a large portion of the CEL strongly reduces growth and abolishes pathogenicity in tomato.

Bacterial Proteins↗
PubMed1995

The genomic region of rbcLS in Synechococcus sp. PCC 7942 contains genes involved in the ability to grow under low CO2 concentration and in chlorophyll biosynthesis.

Several genes involved in the ability of Synechococcus sp. PCC 7942 to grow under different CO2 concentrations were mapped in the genomic region of rbcLS (the operon encoding the large and small subunits of ribulose-1,5-bisphosphate carboxylase/oxygenase). Insertion of a cartridge encoding kanamycin resistance within open reading frame (ORF) 78, designated ccmJ, located 7 kb upstream of rbcLS, resulted in a kanamycin-resistant, high-CO2-requiring mutant, M3, which does not contain normal carboxysomes. ccmJ shows significant homology to csoS1 encoding a carboxysomal shell polypeptide in Thiobacillus neopolitanus. Analysis of the polypeptide pattern of a carboxysome-enriched fraction indicated several differences between the wild type and the mutant. The amount of the ribulose-1,5-bisphosphate carboxylase/oxygenase subunits was considerably smaller in the carboxysomal fraction of the mutant when compared to the wild type. On the basis of the sequence analyses, ORF286 and ORF466, located downstream of ccmJ, were identified as chlL and chlN, respectively, which are involved in chlorophyll biosynthesis in the dark.

Algal Proteins↗
PubMed1990

Structure of the rhsA locus from Escherichia coli K-12 and comparison of rhsA with other members of the rhs multigene family.

The complete nucleotide sequence of the rhsA locus and selected portions of other members of the rhs multigene family of Escherichia coli K-12 have been determined. A definition of the limits of the rhsA and rhsC loci was established by comparing sequences from E. coli K-12 with sequences from an independent E. coli isolate whose DNA contains no homology to the rhs core. This comparison showed that rhsA comprises 8,249 base pairs (bp) in strain K-12 and that the Rhs0 strain, instead, contains an unrelated 32-bp sequence. Similarly, the K-12 rhsC locus is 9.6 kilobases in length and a 10-bp sequence resides at its location in the Rhs0 strain. The rhsA core, the highly conserved portion shared by all rhs loci, comprises a single open reading frame (ORF) 3,714 bp in length. The nucleotide sequence of the core ORF predicts an extremely hydrophilic 141-kilodalton peptide containing 28 repeats of a motif whose consensus is GxxxRYxYDxxGRL(I or T). One of the most novel aspects of the rhs family is the extension of the core ORF into the divergent adjacent region. Core extensions of rhsA, rhsB, rhsC, and rhsD add 139, 173, 159, and 177 codons to the carboxy termini of the respective core ORFs. For rhsA, the extended core protein would have a molecular mass of 156 kilodaltons. Core extensions of rhsB and rhsD are related, exhibiting 50.3% conservation of the predicted amino acid sequence. However, comparison of the core extensions of rhsA and rhsC at both the nucleotide and the predicted amino acid level reveals that each is highly divergent from the other three rhs loci. The highly divergent portion of the core extension is joined to the highly conserved core by a nine-codon segment of intermediate conservation. The rhsA and rhsC loci both contain partial repetitions of the core downstream from their primary cores. The question of whether the rhs loci should be considered accessory genetic elements is discussed but not resolved.

Amino Acid Sequence↗
PubMedDate not supplied

Characterization and nucleotide sequence of a colicin-release gene in the hic region of plasmid ColE3-CA38.

Downstream from its colicin and immunity genes (col. imm), Escherichia coli plasmid ColE3-CA38 contains a 0.81-kb DNA segment, the hic region, which is required for high colicin production. Characterization of derived plasmids, carrying the col-imm operon but varying in the hic region, showed that the latter functions in lacuna production, colicin release, cell death, and lysis. The hic gene expression after induction was shown to be dependent on the col gene promoter. The nucleotide sequence of the 0.81-kb region was determined and the hic gene localized to its imm-distal portion following an open reading frame (ORF) with no known function. There are two overlapping ORFs in that portion of the sequence, one of which was identified as the hic gene by its partial homology to lysis gene H of CloDF13. The 3' half of the hic gene is non-essential and contains a terminator-like DNA sequence. Preceding the gene, there are also inverted repeats which may attenuate its transcription.

Amino Acid Sequence↗
PubMed1999

Phylogenetic evidence for Ty1-copia-like endogenous retroviruses in plant genomes.

SIRE-1 is a multi-copy, Ty1-copia-like retroelement family found in the genome of Glycine max. A sequenced SIRE-1 genomic copy has an uninterrupted ORF that can be translated into a gag-pol polyprotein, followed by an unprecedented second ORF whose conceptual translation yielded a theoretical protein predicted to possess many of the same secondary structural elements found in mammalian retroviral envelope proteins. Similar, but clearly pseudogenic, envelope-like sequences were recovered from conceptual translations of 10 Arabidopsis GenBank accessions. All were associated with identifiable Ty1-copia-like retroelements. Phylogenetic analysis of the adjacent ribonuclease H regions from these sequences and three similarly endowed elements, two from maize and one from tomato, indicate that the 14 elements constitute a monophyletic group distinct from several closely related plant Ty1-copia-like elements in which pol is immediately followed by a downstream LTR. The conservation of identifiable env-like gene features suggests that these plant elements are endogenous retroviruses whose ancestors were acquired from animal vectors. The finding that the env and env-less retroelements identified in this study form distinct lineages does not support the hypothesis that horizontal transmission of retrotransposons is sponsored by ancestral infectious retroviruses that subsequently lost all traces of env genes.

Endogenous Retroviruses↗
PubMed1996

Molecular analysis of the replication elements of the broad-host-range RepA/C replicon.

RepA/C is a replicon specific to the IncA/C incompatibility group of plasmids and was isolated recently from plasmid RA1. The sequence of this autoreplicative region was established; it contains 13 repeats, suggesting that the replicon uses iterons to control its copy number. The sequence contains two ORFs, one potentially coding for a 33-kDa protein (ORF1) and a second potentially coding for a 14-kDa protein (ORF2) (Llanes et al., 1994b). In this work, using an in vitro transcription/translation system, we detected a polypeptide whose size corresponded well to that of the deduced product of ORF1. Deletion and insertion mutation analysis showed that ORF1 is essential for replication; it encodes an initiator protein (called RepA). ORF2 was not essential for replication in Escherichia coli and its function remains to be determined. Using complementation experiments, the replication origin (ori) of RepA/C was defined. The ori was located in a 600-bp fragment downstream from repA, containing 10 direct repeats. To study the control of repA expression, a transcriptional fusion PrepA::lacZ was constructed. Its analysis showed that repA is transcriptionally autoregulated as are most repA genes of replicons controlled by iterons.

Cloning, Molecular↗
PubMed1996

Identification and nucleotide sequence of the thymidine kinase gene of canine herpesvirus.

This paper presents the entire nucleotide sequence of the thymidine Kinase (TK) gene of canine herpesvirus (CHV). The gene was located within a 2.1 kbp EcoRV fragment by Southern-blot hybridization with a probe derived from the known feline herpesvirus type 1 (FHV-1) TK gene. An open reading frame (ORF) of 987 nucleotides, capable of encoding a TK translation product of 328 amino acids, was identified. Alignment of the predicted amino acid sequence of the CHV TK with other herpesvirus TKs revealed homologies of 25-47%. The proposed nucleotide-binding site and thymidine-binding site sequences of known herpesvirus TKs could be aligned with similar sequences in CHV TK. Northern-blot analysis revealed 1.3 kb and 5.0 kb mRNAs as the TK-specific transcripts. It is probable that the 1.3 kb transcript codes for the CHV TK and that the 5.0 kb transcript codes for the CHV TK and the downstream sequence.

Amino Acid Sequence↗