Accueil / Information / Aller plus loin... / Aériens / Pollens / Pollens d’arbres / Les Pinacées

Les Pinacées

jeudi 4 mars 2010, par Allerdata


Les pinacées appartiennent à l’ordre des Pinales (ou Coniférales), comme les Cupressacées.

Les pollens de pins et de cèdres du genre Cedrus sont considérés comme peu allergisants (cf. Les Cupressacées pour la taxonomie des "cèdres").


Plusieurs études ont montré une prévalence basse de positivité en TC pour différentes espèces de pin, dans des pays variés (Europe, USA, etc…) : 1,5 à 3 % des atopiques.

Ce faible taux est rencontré aussi dans des régions fortement exposées comme à Bordeaux .

Quelques rapports font état d’un impact clinique réel :

  • le cèdre déodar en Inde
  • le pin maritime (Pinus pinaster) en Galice où 6 des 10 patients n’étaient réactifs qu’au pollen de pin
  • ou le pin de Monterey (Pinus radiata) au Pays Basque .

La faible prévalence apparente de l’allergie aux pollens de pin, lesquels sont pourtant émis en grande quantité et peuvent parcourir de grandes distances, pourrait résulter :

  • de la grande taille des grains de pollen (60-100µ)
  • dans certaines régions, d’une pollinisation à une période synchrone avec celle de pollens plus « convaincants » (fin avril à juillet)
  • de l’utilisation d’extraits commerciaux peu pertinents du fait de difficultés dans l’obtention de ces extraits (exine cireuse, faible contenu en protéines, etc..) :
    • Une étude bordelaise notait que sur 27 tests cutanés positifs pour P. pinaster seulement 5 étaient positifs aussi pour le pin sylvestre (P. sylvestris). Pourtant ces 2 pollens croisent entre eux
    • Dans l’étude de Mari à Rome , l’extrait de pin se démarquait nettement en étant peu souvent positif (7%) parmi les 440 patients poly-polliniques : en effet, ce groupe était défini comme étant positif pour au moins 12 des 23 pollens testés en TC !
    • Avec des extraits maison, des patients Basques avec forte suspicion de pollinose au pin (symptômes en février-mars, avec Bétulacées et Cupressacées négatives) étaient bien positifs en TC pour le pollen de pin local (P . radiata), mais aussi pour d’autres espèces de pin . En immuno-blot, des bandes IgE-réactives étaient vues chez de nombreux patients à 42 kDa et au-delà (présence de CCD ?), et à 6-8 kDa pour 38% des patients. Cette réactivité à 6-8 kDa fait évoquer un panallergène comme la polcalcine, mais la bande était vue aussi souvent chez les mono-positifs pour le pin (34 sujets/69) que chez les sujets réactifs au pin et aux graminées.

La nature de cette bande 6-8 kDa reste donc à élucider. De même que celle à 42 kDa qui pourrait s’avérer spécifique du pin.

Réactivités croisées entre pollens de Pinacées et d’autres pollens

La réactivité croisée avec d’autres types de pollens a aussi été peu étudiée :

  • réactivité croisée avec l’olivier , laquelle pourrait provenir de CCD, ces derniers ayant été, sans surprise, confirmés être présents dans le pollen de pin ,
  • une inhibition partielle de l’ivraie par P. radiata a été trouvée .
  • Et une absence de réactivité croisée entre le pollen de pin et celui de genévrier a été notée (citée par ), de même qu’entre le pollen de pin et celui du cyprès commun .

Bien qu’appartenant au même ordre des Pinales, les Pinacées et les Cupressacées présentent des différences dans la séquence des protéines homologues qui ne favorisent pas une réactivité croisée. Cela a été vérifié avec des allergènes de Cupressacées comme Jun a 1 (genévrier) ou Cry j 2 (cèdre du Japon) . Le cas des profilines et des polcalcines, panallergènes des pollens en général, mériterait d’être étudié cependant.

[1] - Nocent C, Raherison C, Portel L, N'Guyen L, Lheureux M, Taytard A, et al. Étude de la sensibilisation au pollen de pin maritime (Pinus pinaster) dans la région bordelaise. Rev Fr Allergol Immunol Clin 2005;45:298-302
Il existe dans la région bordelaise un très grand nombre de Pinus pinaster (pin maritime) responsables au printemps d'une forte pollinisation. Nous avons étudié prospectivement la sensibilisation à ce pollen dans une population de malades adressés en consultation de pneumoallergologie. On retrouvait chez 1,9 % de la population étudiée une sensibilisation au pollen de P. pinaster, soit une sensibilisation de 3 % parmi les sujets atopiques. Aucun d'entre eux n'avait de monosensibilisation, les tests cutanés positifs au pin maritime étant le plus souvent associés à une sensibilisation à d'autres pneumallergènes. Ces patients présentaient essentiellement des symptômes d'asthme et de rhinite, avec parfois des symptômes de conjonctivite. Nous n'avons pas mis en évidence de caractéristiques particulières parmi les patients sensibilisés. Cette étude confirme le faible pouvoir allergisant des pollens de pin dans une région où leur concentration atmosphérique est l'une des plus élevées.
↩
[2] - Rawat A, Singh A, Singh AB, Gaur SN, Kumar L, Roy I, et al. Clinical and immunological evaluation of Cedrus deodara pollen: a new allergen from India. Allergy 2000;55:620-626
BACKGROUND: Allergy to pollen from gymnosperms is well documented in the West. However, many allergenic species are native to the Himalayan region of India, and Cedrus deodara (Pinaceae) was selected for allergologic investigation. The objective was to define the allergologic and immunochemical aspects of C. deodara pollen. METHODS: Pollen antigen from C. deodara (CD) was prepared and characterized by biochemical and biologic assays. Specific IgE binding was determined by means of ELISA and immunoblotting. RESULTS: CD pollen antigen caused marked skin sensitivity in 7.5% of an atopic population. A significantly elevated level of CD-specific IgE antibodies was observed in 65.8% of the skin-positive patients. Immunoblotting showed protein fractions of 37, 44, 58, and 78 kDa with 100% binding with the patients' sera suspected to be due to carbohydrate moieties. CONCLUSIONS: Patients from the Himalayan region, where CD occurs naturally, were sensitized more than patients from distant places. The immunochemical characterization revealed multiple protein fractions from low to very high molecular mass (14-126 kDa) mostly in the acidic pI range. CD pollen has been recognized as a new allergen from India for the first time. The role of pollen as a causative agent of respiratory allergic disorders is very well established, as is evident from the recent increase of reports from across the world (1-4). India is blessed with the richest flora on the earth, from alpine tundra to Rajasthan desert. Consequently, it provides considerable variation in the quality and quantity of airborne pollen in different ecogeographic regions of the country (5-8). Although studies on the allergenic properties of airborne pollen from various species have been carried out by several workers in India (9-12), information on allergy to aerial pollen from Himalayan tree species has been completely
↩
[3] - Marcos C, Rodriguez F, Ildefonso L, Jato V, Gonzalez R. Pinus pollen aerobiology and clinical sensitization in northwest Spain. Ann Allergy Asthma Immunol 2001;87:39-42
BACKGROUND: Pinus pollen allergy has been generally considered to be rare and clinically insignificant. In our geographical area, Pinus pollen constitutes one of the most predominant pollen together with Poaceae and Urticaceae pollen. Pinus pinaster and Pinus radiata are the main species . OBJECTIVE: This work aimed to determine the atmospheric fluctuations and the existence of patients monosensitized to Pinus pollen in our region . METHODS: Patients attending our outpatient clinic in the last 4 years with positive cutaneous tests to Pinus pollen and with respiratory symptoms were selected. They were skin tested with commercial extracts of a battery of inhalants including Pinus pollen. Serologic specific IgE to Pinus pollen was performed by CAP system (Pharmacia & Upjohn, Uppsala, Sweden). Airborne Pinus pollen counts in our city were obtained for a 5-year period (1995 to 1999) . RESULTS: We present 10 patients with sensitivity to Pinus pollen and with symptomatology coinciding with Pinus pollen season (February to April). Most of these patients were monosensitizated to Pinus pollen and suffered from seasonal rhinoconjunctivitis. Pinus pollen is present in our area in large amounts from February to April with a peak pollen count in March and April . CONCLUSIONS: Pinus pollen may be an important allergen since by itself can be the only cause of allergic disease. Therefore, we think that it must be taken into account in patients living in areas with high Pinus pollen concentrations and with seasonal respiratory disease.
↩
[4] - Gastaminza G, Lombardero M, Bernaola G, Antepara I, Muñoz D, Gamboa PM et al. Allergenicity and cross-reactivity of pine pollen. Clin Exp Allergy 2009;39:1438-1446
BACKGROUND: Pine pollen has long been considered a non-allergenic pollen. The large size of the grain and its low levels of proteins are the main reasons invoked to explain this low allergenicity. The aim of this study was to describe the main allergenic bands of Pinus radiata (PR) and its cross-reactivity with other pine species, other conifers and grass pollen . METHODS: Sixty-five pine-pollen-allergic patients (51% also sensitized to grass pollen) were studied. Skin prick tests (SPT) to a battery of allergens including PR, Pinus pinea, Pinus sylvestris, Pinus nigra and Cupressus sempervirens pollens and specific IgE determination to PR and Pinus strobus were performed. IgE-immunoblotting to a PR extract and other pine pollens was also carried out. UniCAP inhibition and immunoblotting inhibition studies were performed to assess the cross-reactivity between different pollens . RESULTS: The SPTs were positive with all the pine pollen extracts tested in 69% of the patients. Specific IgE was positive to PR or P. strobus in 77% of the patients, and to Lolium perenne in 51%. Nine different allergenic bands were detected. The two main allergens were a 42 kDa band recognized by 85% of the patients and a band of approximately 6-8 kDa recognized by 40%. A high degree of cross-reactivity was observed between different pine pollen species, but not between pines and C. sempervirens pollen. A partial cross-reactivity could be seen between pine and grass pollens only in patients also sensitized to L. perenne . CONCLUSIONS: Pine pollen should be considered as a potential allergenic pollen especially where this pollen is abundant. The detection of a high number of patients that were monosensitized to pine pollen suggests the possibility of treating these patients with specific immunotherapy.
↩
[5] - Nocent C, Raherison C, Portel L, N'Guyen L, Lheureux M, Taytard A, et al. Étude de la sensibilisation au pollen de pin maritime (Pinus pinaster) dans la région bordelaise. Rev Fr Allergol Immunol Clin 2005;45:298-302
Il existe dans la région bordelaise un très grand nombre de Pinus pinaster (pin maritime) responsables au printemps d'une forte pollinisation. Nous avons étudié prospectivement la sensibilisation à ce pollen dans une population de malades adressés en consultation de pneumoallergologie. On retrouvait chez 1,9 % de la population étudiée une sensibilisation au pollen de P. pinaster, soit une sensibilisation de 3 % parmi les sujets atopiques. Aucun d'entre eux n'avait de monosensibilisation, les tests cutanés positifs au pin maritime étant le plus souvent associés à une sensibilisation à d'autres pneumallergènes. Ces patients présentaient essentiellement des symptômes d'asthme et de rhinite, avec parfois des symptômes de conjonctivite. Nous n'avons pas mis en évidence de caractéristiques particulières parmi les patients sensibilisés. Cette étude confirme le faible pouvoir allergisant des pollens de pin dans une région où leur concentration atmosphérique est l'une des plus élevées.
↩
[6] - Marcos C, Rodriguez F, Ildefonso L, Jato V, Gonzalez R. Pinus pollen aerobiology and clinical sensitization in northwest Spain. Ann Allergy Asthma Immunol 2001;87:39-42
BACKGROUND: Pinus pollen allergy has been generally considered to be rare and clinically insignificant. In our geographical area, Pinus pollen constitutes one of the most predominant pollen together with Poaceae and Urticaceae pollen. Pinus pinaster and Pinus radiata are the main species . OBJECTIVE: This work aimed to determine the atmospheric fluctuations and the existence of patients monosensitized to Pinus pollen in our region . METHODS: Patients attending our outpatient clinic in the last 4 years with positive cutaneous tests to Pinus pollen and with respiratory symptoms were selected. They were skin tested with commercial extracts of a battery of inhalants including Pinus pollen. Serologic specific IgE to Pinus pollen was performed by CAP system (Pharmacia & Upjohn, Uppsala, Sweden). Airborne Pinus pollen counts in our city were obtained for a 5-year period (1995 to 1999) . RESULTS: We present 10 patients with sensitivity to Pinus pollen and with symptomatology coinciding with Pinus pollen season (February to April). Most of these patients were monosensitizated to Pinus pollen and suffered from seasonal rhinoconjunctivitis. Pinus pollen is present in our area in large amounts from February to April with a peak pollen count in March and April . CONCLUSIONS: Pinus pollen may be an important allergen since by itself can be the only cause of allergic disease. Therefore, we think that it must be taken into account in patients living in areas with high Pinus pollen concentrations and with seasonal respiratory disease.
↩
[7] - Mari A. Multiple pollen sensitization: a molecular approach to the diagnosis. Int Arch Allergy Immunol 2001;125:57-65
BACKGROUND: Sensitization to multiple pollen species is a frequent diagnostic event. Several allergenic molecules with a high level of homology have been identified in divergent pollen families and named panallergens. METHODS: We sought to define the criteria to evaluate the prevalence of the multiple pollen sensitization, to identify specific markers of this condition, and to correlate them with the underlying allergic disease. Patients presenting an allergic respiratory disease underwent skin testing with 23 pollens. Patients fulfilling predefined selection criteria were grouped and classified as having multiple pollen sensitization. Patients in each subgroup were tested for IgE to rBet v 2, rJun o 2, rBet v 1, rPhl p 5 and bromelain. Demographical, allergological and clinical data were recorded in the subgroup of patients with multiple pollen sensitization. RESULTS: Seventeen percent of the pollen-sensitized patients formed the multiple pollen-sensitized subgroup. These subjects were positive for most of the pollen species tested regardless of known exposure to them. None of the subjects sensitized to less than six pollen species were positive to panallergens, whereas 55% of the sera of the multiple pollen-sensitized group were positive to rBet v 2, and 15% to rJun o 2. IgE to rBet v 1 and rPhl p 5 were found positive in all the subgroups. Age, gender, bronchial asthma, oral allergy syndrome, skin test reactivity and previous specific immunotherapy differed significantly when these two subsets were considered. CONCLUSIONS: Allergy diagnosis based on allergenic molecules is crucial in the patient with multiple pollen sensitization. This condition appears to be determined by the sensitization to defined allergenic components (panallergens) rather than by pollen of multiple species as such. Detection of IgE to nonpanallergenic molecules allows to identify more relevant allergenic sources. Clinical aspects of the underlying allergic disease (e.g. asthma and oral allergy syndrome) seem to be differently related to IgE reactivity to panallergens
↩
[8] - Gastaminza G, Lombardero M, Bernaola G, Antepara I, Muñoz D, Gamboa PM et al. Allergenicity and cross-reactivity of pine pollen. Clin Exp Allergy 2009;39:1438-1446
BACKGROUND: Pine pollen has long been considered a non-allergenic pollen. The large size of the grain and its low levels of proteins are the main reasons invoked to explain this low allergenicity. The aim of this study was to describe the main allergenic bands of Pinus radiata (PR) and its cross-reactivity with other pine species, other conifers and grass pollen . METHODS: Sixty-five pine-pollen-allergic patients (51% also sensitized to grass pollen) were studied. Skin prick tests (SPT) to a battery of allergens including PR, Pinus pinea, Pinus sylvestris, Pinus nigra and Cupressus sempervirens pollens and specific IgE determination to PR and Pinus strobus were performed. IgE-immunoblotting to a PR extract and other pine pollens was also carried out. UniCAP inhibition and immunoblotting inhibition studies were performed to assess the cross-reactivity between different pollens . RESULTS: The SPTs were positive with all the pine pollen extracts tested in 69% of the patients. Specific IgE was positive to PR or P. strobus in 77% of the patients, and to Lolium perenne in 51%. Nine different allergenic bands were detected. The two main allergens were a 42 kDa band recognized by 85% of the patients and a band of approximately 6-8 kDa recognized by 40%. A high degree of cross-reactivity was observed between different pine pollen species, but not between pines and C. sempervirens pollen. A partial cross-reactivity could be seen between pine and grass pollens only in patients also sensitized to L. perenne . CONCLUSIONS: Pine pollen should be considered as a potential allergenic pollen especially where this pollen is abundant. The detection of a high number of patients that were monosensitized to pine pollen suggests the possibility of treating these patients with specific immunotherapy.
↩
[9] - Gonzalez EM, Villalba M, Rodriguez R. Allergenic cross-reactivity of olive pollen. Allergy 2000;55:658-663
BACKGROUND: Sera of patients allergic to olive (Olea europaea) pollen were used to analyze the IgE cross-reactivity between olive-pollen extract and other pollens obtained from phylogenetically unrelated species. METHODS: We used IgE immunostaining of pollen extracts blotted to nitrocellulose membranes after SDS-PAGE and inhibition analysis of this binding. RESULTS: A high inhibition of the IgE binding on olive-pollen extract was exhibited by birch, mugwort, pine, and cypress pollens, suggesting that these extracts contain proteins which share common epitopes and thus can be recognized by olive-allergic sera. IgE binding to Gramineae pollen extracts was not inhibited by olive-pollen extract, indicating a primary sensitization of the patients to these species. From the inhibition assays, the presence of an allergen of 45 kDa in the olive pollen, which has no homologous counterparts in other allergenic species, has been inferred. CONCLUSIONS: Olive pollen contains allergens which cross-react with pollens from unrelated species, a fact that could simplify the diagnosis and treatment of pollinosis.
↩
[10] - Mari A, Iacovacci P, Afferni C, Barletta B, Tinghino R, Di Felice G, et al. Specific IgE to cross-reactive carbohydrate determinants strongly affects the in vitro diagnosis of allergic diseases. J Allergy Clin Immunol 1999;103:1005-1011
BACKGROUND: Cross-reacting carbohydrate determinants (CCDs) are antigenic structures shared by allergenic components from taxonomically distant sources. The case history of a patient with a great discrepancy between skin test and specific IgE results led us to investigate the role of these determinants in his specific case and in an allergic population. OBJECTIVE: We sought to determine the role of CCDs in causing false-positive and clinically irrelevant results in in vitro tests. METHODS: The involvement of CCDs was studied by specific IgE inhibition by using glycoproteins with a known carbohydrate structure. Direct and inhibition assays were performed by commercially available systems, in-house ELISA, and the immunoblotting technique. The binding to the periodate-oxidated carbohydrate structure of glycoproteins and allergenic extracts was also evaluated. A comparative study between skin test and specific IgE responses to the antigens studied was carried out in 428 consecutive allergic subjects. RESULTS: All the tests performed suggested that cross-reacting carbohydrate epitopes were the cause of false-positive specific IgE results in one of the commercial systems and the high reactivity in all the solid-phase in vitro tests. None of the cross-reacting carbohydrate allergens yielded a positive skin test response. Periodate treatment caused variable degrees of reduction of IgE binding to the different antigens studied, indicating that CCDs played a different role in each of them. About 41% of patients allergic to pollen had specific IgE for a glycoprotein, without a positive skin test response to the same molecule. CONCLUSIONS: CCDs must be taken into account when evaluating the clinical relevance of positive results in in vitro specific IgE assays, at least in the diagnosis of patients with pollen allergy. Commercial systems should be carefully assessed for the ability to detect specific IgE for carbohydrate determinants to avoid false-positive or clinically irrelevant results.
↩
[11] - Cornford CA, Fountain DW, Burr RG. IgE-binding proteins from pine (Pinus radiata D. Don) pollen: evidence for cross-reactivity with ryegrass (Lolium perenne). Int Arch Allergy Appl Immunol 1990;93:41-46
A complex mixture of pine (Pinus radiata D. Don) pollen proteins are rapidly released into aqueous solutions. IgE-binding proteins have been identified in these extracts using combined SDS-PAGE immunoblotting techniques. These IgE-binding proteins were detected using atopic patient and commercial pooled human sera known to be high in ryegrass-specific IgE. Enzyme-immunoassay inhibition studies revealed that leached P. radiata pollen proteins could partially inhibit serum IgE binding to ryegrass RAST discs thus providing preliminary evidence for allergen cross-reactivity between these two unrelated species.
↩
[12] - Weber RW. Cross-reactivity of plant and animal allergens. Clin Rev Allergy Immunol 2001;21:153-202
↩
[13] - Gastaminza G, Lombardero M, Bernaola G, Antepara I, Muñoz D, Gamboa PM et al. Allergenicity and cross-reactivity of pine pollen. Clin Exp Allergy 2009;39:1438-1446
BACKGROUND: Pine pollen has long been considered a non-allergenic pollen. The large size of the grain and its low levels of proteins are the main reasons invoked to explain this low allergenicity. The aim of this study was to describe the main allergenic bands of Pinus radiata (PR) and its cross-reactivity with other pine species, other conifers and grass pollen . METHODS: Sixty-five pine-pollen-allergic patients (51% also sensitized to grass pollen) were studied. Skin prick tests (SPT) to a battery of allergens including PR, Pinus pinea, Pinus sylvestris, Pinus nigra and Cupressus sempervirens pollens and specific IgE determination to PR and Pinus strobus were performed. IgE-immunoblotting to a PR extract and other pine pollens was also carried out. UniCAP inhibition and immunoblotting inhibition studies were performed to assess the cross-reactivity between different pollens . RESULTS: The SPTs were positive with all the pine pollen extracts tested in 69% of the patients. Specific IgE was positive to PR or P. strobus in 77% of the patients, and to Lolium perenne in 51%. Nine different allergenic bands were detected. The two main allergens were a 42 kDa band recognized by 85% of the patients and a band of approximately 6-8 kDa recognized by 40%. A high degree of cross-reactivity was observed between different pine pollen species, but not between pines and C. sempervirens pollen. A partial cross-reactivity could be seen between pine and grass pollens only in patients also sensitized to L. perenne . CONCLUSIONS: Pine pollen should be considered as a potential allergenic pollen especially where this pollen is abundant. The detection of a high number of patients that were monosensitized to pine pollen suggests the possibility of treating these patients with specific immunotherapy.
↩
[14] - Xie L, Midoro-Horiuti T, Schein C, Braun W, Goldblum RM. Molecular Biodiversity of Conifers Might Be Used to Design Specific Immunotherapy. J Allergy Clin Immunol 2005;115(2 suppl.):S89
RATIONALE: The molecular biodiversity of plants may provide an opportunity to use IgE epitope analysis to identify hypoallergenic homologues of Jun a 1 for use in specific immunotherapy METHODS: A library of sequences for Jun a 1 homologues was created by sequencing genomic DNA from 140 Juniperus/Cupressus species. 80 Pinus sequences were mined from GeneBank. Mutational analysis of IgE epitopes was carried out by alanine substitution in synthetic peptides and tested by immunoassay. The physico-chemical characteristics of amino acid sequences of IgE epitopes were compared to Jun a 1, using quantitative structure-activity relationship (QSAR). The results were expressed as property distance (PD) values RESULTS: The sequences of linear IgE epitopes 2 and 3 of the Jun a 1 homologues from Juniperus/Cupressus species are highly conserved However, sequence variants were found within epitopes 1 and 4. 9 out of 140 homologues had PD value >5 in epitope 1 region. In Pinaceae, variants with high PD values were found at each epitope site. Mutational analysis by alanine substitution within epitope 4 showed that single amino acid changes at aa 296, 297, 300 and 301 resulted in loss or reduction of human IgE binding. We found that 3 Pinaceae sequences had similar amino acid changes in one of those sites CONCLUSIONS: The high PD values for some substitutions in IgE epitopes suggest that some Jun a 1 homologues are good candidates for hypoallergenic vaccines. These findings suggest the feasibility of identifying structural variants within the pollen of naturally occurring variants
↩
[15] - Futamura N, Kusunoki Y, Mukai Y, Shinohara K. Characterization of Genes for a Pollen Allergen, Cry j 2, of Cryptomeria japonica. Int Arch Allergy Immunol 2007;143:59-68
BACKGROUND: Cry j 2 is one of the major pollen allergens of Cryptomeria japonica. The polymorphism of Cry j 2 isoforms and the conservation of the structure of Cry j 2 in coniferous species remain to be analyzed . METHODS: A cDNA library derived from the pollen of C. japonica was screened using a fragment of Cry j 2 cDNA. Restriction fragment length polymorphism analysis was performed to examine the diversity of Cry j 2 genes. The promoters of Cry j 2 genes were isolated with a commercially available cloning kit. Clonal variations in the expression of Cry j 2 in pollen were examined by RNA gel blot analysis, and the conservation of the structure of the Cry j 2 gene in coniferous species was evaluated by DNA gel blot analysis . RESULTS: We isolated three cDNA clones encoding novel isoforms of Cry j 2. We also sequenced a total of 16 promoter regions from 10 specimens. The sequences of promoter regions of Cry j 2 genes were highly divergent. The amount of Cry j 2 mRNA also varied considerably. The Cry j 2 gene was found to be conserved among species belonging to Taxodiaceae and Cupressaceae but to vary between Taxodiaceae and Pinaceae . CONCLUSIONS: The coding and promoter regions of Cry j 2 genes contain large numbers of polymorphisms. Our analysis revealed large variations in the expression of Cry j 2 at the transcriptional level, and we suggest that conserved homologs of Cry j 2 confer cross-allergenicity among Taxodiaceae and Cupressaceae.
↩
Imprimer la bibliographie