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1.
Mol Biol Rep ; 49(2): 1151-1159, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35013863

RESUMO

BACKGROUND: Despite commonly use for treatment of type II diabetes, possible effects of glipizide on nuclear transport and DNA damage in cells are unknown. Since clinical response of glipizide may change with aging, the aim of the study was to investigate the effect of glipizide by comparing mature and senescent adipocytes. METHODS AND RESULTS: The effects of glipizide were investigated in 3T3-L1 adipocytes. Effective and lethal doses were determined by real-time monitoring iCELLigence system. Comet assay was performed to determine DNA damage and quantitative PCR was conducted to detect gene expression levels. RAN expressions were found to be up regulated in mature 180 µM glipizide treated adipocytes compared to control group (p < 0.05); whereas down regulated in senescent 180 µM glipizide treated adipocytes compared to their control adipocytes (p < 0.05). Olive Tail Moment values were significantly higher in mature 180 µM glipizide treated adipocytes (MTG) and senescent 180 µM glipizide treated adipocytes (STG) comparing their untreated controls (p < 0.001 and p < 0.001 respectively). Also class 5 comets that shows severe DNA damage were found to be higher in both MTG and STG groups than their controls (p < 0.001 and p < 0.001, respectively). OTM values were higher in STG than MTG (p < 0.001). CONCLUSIONS: This is the first study that reports glipizide caused DNA damage increasing with senescence in adipocytes. As a response to glipizide treatment Ran gene expression increased in mature; and decreased in senescent adipocytes. Further studies are needed to reveal the effect of glipizide on DNA and nuclear interactions in molecular level.


Assuntos
Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Glipizida/farmacologia , Células 3T3-L1/efeitos dos fármacos , Transporte Ativo do Núcleo Celular/fisiologia , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Animais , Diferenciação Celular , Dano ao DNA/genética , Glipizida/efeitos adversos , Glipizida/metabolismo , Camundongos
2.
Mol Biol Rep ; 49(3): 1827-1836, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35076848

RESUMO

BACKGROUND: Programmed Cell Death-1 (PD-1) together with Programmed Death Ligand 1 (PDL-1) have crucial roles in anti-tumor immune response, cancer susceptibility and prognosis. Since PD-1 and PDL-1 have been considered as important genetic risk factors in cancer development and their functions can be affected by polymorphic sites, we investigated the effects of PD-1 rs2227981, rs2227982, rs36084323 and PDL-1 rs2282055, rs822336 gene polymorphisms on colorectal cancer (CRC) risk and prognosis in Turkish subjects. METHODS AND RESULTS: Our study group consisted of 5-FU or Capacitabine prescribed CRC diagnosed patients and healthy controls. Genotype analyses of PD1 and PDL-1 polymorphisms were performed with Agena MassARRAY platform. rs36084323 CT genotype frequency was found to be higher in controls compared to cases (p < 0.001). rs36084323 CT genotype was highly associated with reduced CRC risk compared to CC genotype (OR 0.068, 95% CI 0.022-0.211, p < 0.001). In adjusted analysis, rs2282055 GG genotype was found to be associated with reduced CRC risk (OR 0.271, 95% CI 0.078-0.940, p = 0.040). rs2282055 TT genotype was found to be related to longer progression-free (Bonferroni corrected Log rank p = 0.013) and overall survival (Bonferroni corrected Log rank p = 0.009) to that of GG genotypes. Patients with rs822336 GC+CC genotypes showed longer overall survival times compared to GG (Log rank p = 0.044). CONCLUSIONS: According to our results, PD-1 rs822336 G > C polymorphism might be useful in predicting CRC prognosis. PDL-1 rs2282055 T > G polymorphism might be useful in predicting both CRC risk and prognosis. Further studies should be conducted in larger and different populations to clear the roles of PD-1 and PDL-1 polymorphisms in CRC risk and prognosis.


Assuntos
Antígeno B7-H1/genética , Neoplasias Colorretais , Receptor de Morte Celular Programada 1/genética , Estudos de Casos e Controles , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/genética , Predisposição Genética para Doença , Genótipo , Humanos , Polimorfismo de Nucleotídeo Único/genética
3.
Mol Biol Rep ; 47(12): 9399-9408, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33185830

RESUMO

Adipocyte death is important in obesity development. Understanding and prevention of adipocyte deaths may be a molecular approach in the treatment. In the study, we aimed to understand role of Niban gene, which acts as an anti-apoptotic molecule as a response to stress conditions, in adipocytes. 3T3-L1 adipocytes were treated with different doses of linoleic acid, hydrogen peroxide and ethanol; and proliferation of the cells examined with real time monitoring iCELLingence system. Gene expression levels were measured by q-PCR. As a response to 24h 480 µM linoleic acid treatment, Niban gene expression was found to be higher than control group (p = 0.008), whereas 24 h 90 mM ethanol treatment was determined to be lower than control group (p = 0.008). The highest value of Niban gene expression among H2O2 treatment groups was detected in 4h 600µM H2O2 in comparison to control group (p = 0.008). To understand role of Niban in adipogenesis, Niban gene expressions were compared between pre-adipocytes and advanced fat accumulated adipocytes and determined to be significantly different (p = 0.042). Our results suggest that Niban might be involved in stress response process in adipocytes. However, the exact molecular role of Niban needs to be investigated in further studies.


Assuntos
Adipócitos/metabolismo , Adipogenia/genética , Apoptose/genética , Dano ao DNA/genética , Expressão Gênica , Peptídeos e Proteínas de Sinalização Intracelular/genética , Obesidade/genética , Estresse Oxidativo/genética , Células 3T3-L1 , Adipócitos/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Etanol/farmacologia , Expressão Gênica/efeitos dos fármacos , Peróxido de Hidrogênio/farmacologia , Ácido Linoleico/farmacologia , Camundongos , Obesidade/patologia , Reação em Cadeia da Polimerase em Tempo Real
4.
Bull Environ Contam Toxicol ; 104(6): 852-857, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32322934

RESUMO

Wastewater (WW) carry considerable amount of chemicals that could have mutagenic or cytotoxic effect from hospital discharges to aquatic environment. Our objective was to determinate the possible mutagenic and toxic effects of hospital originated WWs and effectiveness of the wastewater treatment plants (WTP) functions. In the study the mutagenic and cytotoxic potential of three hospitals and influent/effluent of a treatment plant WW collected in Istanbul and was examined using AMES, XTT, and lactate dehydrogenase (LDH) assays. Mutagenic effects were detected at both hospital discharges and advanced biological wastewater plant. We observed no cytotoxic effect in fibroblasts for LDH and XTT assays whereas high cytotoxicity for all samples was found in hepatocytes by XTT assay. According to the results even if advanced technology is used for treatment of WW, mutagenic and cytotoxic effects still remain, and the present technologies need to be further improved.


Assuntos
Mutagênicos/toxicidade , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/toxicidade , Purificação da Água/métodos , Células 3T3-L1 , Animais , Bioensaio , Sobrevivência Celular/efeitos dos fármacos , Hospitais , Camundongos , Testes de Mutagenicidade , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética
5.
Life (Basel) ; 13(5)2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-37240768

RESUMO

The pomegranate (Punica granatum L.) is one of the fruit species with the oldest cultural history. There are many traits to determine the quality of pomegranate fruits. Among them, soft-seeded feature of pomegranate fruit is important trait for the market value of the fruit. For this reason, the demand for pomegranate varieties with soft seeds has been increasing, especially in recent years. In this study, molecular markers associated with seed hardness were developed to distinguish pomegranate cultivars with soft-seeded feature based on genomic DNA at the early stages of the pomegranate breeding process. For this purpose, pomegranate genotypes and/or cultivars from the population involved in reciprocal crosses of hard-seeded Ernar, medium-hard-seeded Hicaznar, and soft-seeded Fellahyemez cultivars were grouped as soft-seeded or hard-seeded. Further, leaf samples were collected from individuals belonging to each group. Then, the genomic DNA was isolated from each plant separately, and equal amount of genomic DNA from individuals with the similar seed hardness were mixed for bulked segregant analysis (BSA). The bulked genomic DNAs of opposite characters were analyzed by polymerase chain reaction (PCR) using random decamer primers to develop random amplified polymorphic DNA (RAPD) markers associated with soft-seeded or hard-seeded pomegranates. A total of three RAPD markers were determined to distinguish the individuals having soft- or hard-seeded pomegranate genotypes and/or cultivars. As a result of the comparison of the DNA sequences of these RAPD markers, insertion-deletions (inDels) primers were designed to developed and validate a PCR assay to distinguish the soft- and hard-seeded pomegranate genotypes/cultivars from each other. The molecular markers developed in this study will enable us to distinguish soft-seeded pomegranate types easily in a short time at the early stages of the pomegranate breeding programs.

6.
Genet Test Mol Biomarkers ; 26(5): 298-306, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35593899

RESUMO

Objectives: Tumor angiogenesis is known to support the spread and invasion of tumor cells, allow distant organ metastasis and to result in poorer prognoses and increased mortality. Since vascular endothelial growth factor-A (VEGF-A) is the major regulator of angiogenesis, in the present study the associations of the VEGF-A +405G>C and -460C>T polymorphisms with risk, primary tumor location, prognosis and metastasis of colorectal cancer (CRC) were investigated in Turkish subjects. Material and Methods: A total of 153 subjects consist of 74 controls and 79 CRC diagnosed patients were included in the study. VEGF-A +405G>C and -460C>T polymorphisms were analyzed using the Agena MassARRAY platform. Results: The VEGF +405GC+CC genotypes were found to be significantly associated with left colon cancer (unadjusted OR = 5.208 95% CI: 1.064-25.496, p = 0.04). The VEGF -460TT and CT+TT genotypes were associated with reduced liver metastasis risk (OR = 0.080 95% CI: 0.009-0.689 p = 0.02 and OR = 0.191 95% CI: 0.039-0.925, p = 0.04, respectively). Patients with the VEGF +405GG genotype showed longer progression-free survival in response to bevacizumab treatment (Log rank = 6.92, p = 0.03). Conclusion: According to our results, the VEGF +405G>C and -460C>T polymorphisms were found to be associated with CRC prognosis, sidedness and metastases. Our findings need to be replicated in further studies.


Assuntos
Neoplasias Colorretais , Fator A de Crescimento do Endotélio Vascular , Estudos de Casos e Controles , Neoplasias Colorretais/irrigação sanguínea , Neoplasias Colorretais/epidemiologia , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Predisposição Genética para Doença , Genótipo , Humanos , Metástase Neoplásica , Neovascularização Patológica/genética , Polimorfismo de Nucleotídeo Único , Turquia/epidemiologia , Fator A de Crescimento do Endotélio Vascular/genética
7.
Per Med ; 19(5): 435-444, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35880438

RESUMO

Aim: To investigate the association of DPYD, MTHFR and TYMS polymorphisms on 5-fluorouracil (5-FU) related toxicities and patient survival. Materials & methods: A total of 103 colorectal cancer patients prescribed 5-FU were included in the study. Genotyping was conducted for several DPYD, MTHFR and TYMS polymorphisms using a microarray analyzer. Results: DPYD 496A>G polymorphism was found to be significantly associated with 5-FU related grade 0-2, but not severe toxicities (p = 0.02). Furthermore, patients with DPYD 85TC and CC genotypes had longer progression and overall survival times compared to TT genotypes in our study group (log rank = 6.60; p = 0.01 and log rank = 4.40; p = 0.04, respectively). Conclusion: According to our results, DPYD 496AG and GG genotypes might be protective against severe adverse events compared to the AA genotype. Another DPYD polymorphism, 85T>C, may be useful in colorectal cancer prognosis. Further studies for both polymorphisms should be conducted in larger populations to achieve accurate results.


5-fluorouracil (5-FU) is a widely used drug for chemotherapy in colorectal cancer. In this study, we investigated the relationship between the severity of 5-FU induced adverse events and several variations in DPYD, MTHFR and TYMS genes, which encode the enzymes involved in 5-FU metabolism in a total of 103 colorectal patients. We also examined the relationship between the polymorphisms and progression-free and overall survival times of the patients in our study group. Among the variations, DPDY 496A>G polymorphism was found to be associated with 5-FU induced adverse events. Also, the DPYD 85T>C polymorphism was detected to be associated with longer progression-free and overall survival times.


Assuntos
Neoplasias Colorretais , Di-Hidrouracila Desidrogenase (NADP) , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Di-Hidrouracila Desidrogenase (NADP)/genética , Fluoruracila/efeitos adversos , Genótipo , Humanos , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Polimorfismo Genético/genética , Timidilato Sintase/genética
8.
Curr Drug Saf ; 16(3): 252-258, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33413066

RESUMO

BACKGROUND: Clopidogrel has been commonly prescribed as a selective P2Y12 receptor antagonist to reduce heart attack and stroke risk. Nearly 10% of absorbed clopidogrel is metabolized to active forms by cytochrome P450 (CYP) enzymes in the liver and 90% to inactive clopidogrel carboxylate by esterases. OBJECTIVE: Since different forms of clopidogrel have cytotoxic potential, our aim was to determine the effect of 7.5, 40, and 75µM clopidogrel over DNA damage in adipocytes and hepatocytes. METHODS: In the present study, DNA damage was investigated by Comet analysis using 3T3-L1 adipocytes and Alpha Mouse 12 (AML-12) hepatocytes. RESULTS: DNA fragmentation was found to be increased as a response to 7.5 µM, 40 µM, and 75 µM clopidogrel treatment compared to non-treated control groups in AML-12 hepatocytes (p<0.01, p<0.001, p<0.01 respectively) and 3T3-L1 adipocytes (p<0.001, p<0.001 and p<0.001respectively). DNA damage levels as a response to clopidogrel treatment were found to be higher in 3T3-L1 adipocytes than AML-12 hepatocytes. Also, DNA damage levels in adipocytes and hepatocytes were found to increase dose-dependently for 7.5 and 40 µM clopidogrel, whereas decreased as a response to 75 µM. CONCLUSION: According to our results, clopidogrel results in more DNA damage in adipocytes than in hepatocytes. The molecular mechanism of clopidogrel genotoxicity needs to be further investigated especially in adipose tissue.


Assuntos
Adipócitos , Leucemia Mieloide Aguda , Células 3T3-L1 , Animais , Clopidogrel/toxicidade , Dano ao DNA , Hepatócitos , Humanos , Camundongos
9.
Future Cardiol ; 16(6): 645-654, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32583677

RESUMO

Aim: Our aim was to examine the effect of CYP2C9 and VKORC1 polymorphisms on warfarin dose requirements in Turkish patients. Materials & methods: 24 warfarin prescribed patients were included and analyzed for eight VKORC1 and 6 CYP2C9 polymorphisms in the study. Results: Patients with CYP2C9 *1/*1 and VKORC1 -1639 GG and GA genotypes required higher warfarin doses in comparison to wild type VKORC1 genotype. Patients with CYP2C9 *1/*3 and VKORC1 -1639 GG genotypes simultaneously, required the lowest dose of warfarin (4.64 mg/day). Patients with CYP2C9 *1/*1 and VKORC1 9041 AA genotype were found to require higher warfarin doses. Conclusion: Our results provide additional evidence to support the hypothesis that CYP2C9 *2, *3, VKORC1 9041 G > A polymorphisms explain considerable proportion of inter-individual variability in warfarin dose requirement.


Assuntos
Anticoagulantes , Varfarina , Citocromo P-450 CYP2C9/genética , Genótipo , Humanos , Polimorfismo Genético , Vitamina K Epóxido Redutases/genética
10.
J Virol Methods ; 265: 1-8, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30557574

RESUMO

A graft inoculation method coupled with RT-qPCR was developed for monitoring ToCV infection in tomato plants. Ten seed-grown tomato seedlings were graft inoculated with phloem tissue-containing stem segments from a ToCV-infected tomato plants. Another group of tomato seedling were grafted with similar stem segments from a healthy tomato plant as mock inoculated control. The CP gene of ToCV was cloned under the control of T7 promoter and in vitro synthesized RNA was used as a standard for quantification. Total RNA was isolated from leaf samples of ToCV-inoculated and mock-inoculated control plants before the inoculation and 1-60 days post inoculation (dpi). The presence and the titer of ToCV were determined from all ToCV-inoculated or mock-inoculated control plants by RT-qPCR. After 15 dpi, ToCV was detected in 20-30% of graft-inoculated plants. The infection rate then increased progressively and reached to 70-80% by 60 dpi. Titer of ToCV was at the detectable level at 15 dpi and increased and reached to maximum level by 40 dpi and then started to decrease. The results showed that patch grafting is a simple and efficient method for experimental inoculation of ToCV and can be used as an alternative and/or complementary to vector transmission in the laboratories. The patch grafting could be combined with RT-qPCR and used for infecting and quantitative monitoring of ToCV or other phloem-limited viruses in tomato or in other plants.


Assuntos
Crinivirus/isolamento & purificação , Doenças das Plantas/virologia , Reação em Cadeia da Polimerase em Tempo Real/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Crinivirus/genética , Estudos Longitudinais , Folhas de Planta/virologia , Plantas , Carga Viral
11.
Plant Pathol J ; 35(3): 257-273, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31244571

RESUMO

Tomato (Solanum lycopersicum) is one of the most widely grown and economically important vegetable crops in the world. Tomato chlorosis virus (ToCV) is one of the recently emerged viruses of tomato distributed worldwide. ToCV-tomato interaction was investigated at the molecular level for determining changes in the expression of tomato genes in response to ToCV infection in this study. A cDNA library enriched with genes induced in response to ToCV infection were constructed and 240 cDNAs were sequenced from this library. The macroarray analysis of 108 cDNAs revealed that the expression of 92 non-redundant tomato genes was induced by 1.5-fold or greater in response to ToCV infection. The majority of ToCV-induced genes identified in this study were associated with a variety of cellular functions including transcription, defense and defense signaling, metabolism, energy, transport facilitation, protein synthesis and fate and cellular biogenesis. Twenty ToCV-induced genes from different functional groups were selected and induction of 19 of these genes in response to ToCV infection was validated by RT-qPCR assay. Finally, the expression of 6 selected genes was analyzed in different stages of ToCV infection from 0 to 45 dpi. While the expression of three of these genes was only induced by ToCV infection, others were induced both by ToCV infection and wounding. The result showed that ToCV induced the basic defense response and activated the defense signaling in tomato plants at different stages of the infection. Functions of these defense related genes and their potential roles in disease development and resistance to ToCV are also discussed.

12.
Gene ; 512(2): 536-45, 2013 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-23026217

RESUMO

Citrus is one of the most economically important fruit crops growing in subtropical and tropical regions. Most commercially important Citrus varieties are susceptible to cold; therefore, low and freezing temperatures are the main limiting factors for citrus production in subtropical areas. Since Poncirus trifoliata (L.) Raf. is a cold-hardy, interfertile Citrus relative, it serves as a genetic resource for improving cold tolerance in cold sensitive commercial Citrus species. While gene induced in response to long-term cold acclimation was previously identified in Poncirus, early response of Poncirus to cold has not been explored in detail. To identify early cold-responsive genes, a subtractive cDNA library was constructed using 4-h cold-treated and untreated control Poncirus seedlings in this study. A total of 210 randomly picked clones from the subtracted library with cold-induced genes were sequenced. The sequences obtained from the majority of these clones shared homology with previously identified cold-induced and/or environmental stress-regulated genes in other plants. Reverse northern blot analysis of the expression of these cDNAs with cold-treated and untreated control probes revealed that expression of 64 cDNAs was increased two to 11 fold in response to 4-h cold treatment. While the majority of these genes were related with cell rescue, defense, cell death and aging, transcription, metabolism, protein fate, energy, cellular communication and signal transduction, transport facilitation and development, some of them did not show homology with genes with known functions. Individual expression analysis of nine selected genes by semi-quantitative RT-PCR using mRNA from cold-treated and untreated control plants confirmed that the expression of selected cDNAs was all induced in response to cold. The results demonstrated that although a few genes were commonly induced in response to both short and long-term cold acclimation in Poncirus, majority of early cold-responsive genes were different from previously identified late cold-responsive genes in Poncirus.


Assuntos
Temperatura Baixa , Resposta ao Choque Frio/fisiologia , Regulação da Expressão Gênica de Plantas/fisiologia , Genes de Plantas/fisiologia , Poncirus/fisiologia , Plântula/fisiologia , DNA Complementar/biossíntese , Perfilação da Expressão Gênica , Reação em Cadeia da Polimerase Via Transcriptase Reversa
13.
Plant Mol Biol ; 62(1-2): 83-97, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16900323

RESUMO

Citrus is a cold-sensitive genus and most commercially important varieties of citrus are susceptible to freezes. On the other hand, Poncirus trifoliata (L.) Raf. is an interfertile Citrus relative that can tolerate temperatures as low as -26 degrees C when fully cold acclimated. Therefore, it has been used for improving cold tolerance in cold-sensitive commercial citrus rootstock varieties and in attempts to improve scion varieties. In this study, cDNA libraries were constructed from both 2-day cold-acclimated and from non-acclimated Poncirus seedlings using a subtractive hybridization method with the objective of identifying cold-regulated genes. A total of 192 randomly picked clones, 136 from the cold-induced library and 56 from the cold-repressed library, were sequenced. The majority of these clones showed sequence homology to previously identified cold-induced and/or environmental stress-regulated genes in Arabidopsis. In addition, some of them shared homology with cold and/or environmental stress-induced genes previously identified in other herbaceous and woody perennial plants and some showed no homology with sequences in GenBank. When these 192 cDNAs were analyzed by reverse northern blot with cold-acclimated and non-acclimated probes, 92 of the cDNAs displayed significantly increased expression, ranging from 2 to 49-fold, during cold acclimation; all 92 were from the cold-induced library. Surprisingly no clones displayed significantly repressed expression in response to cold. Analysis of a number of selected genes individually in northern blots of mRNA from cold-acclimated and non-acclimated plants largely confirmed the reverse northern analysis, verifying induction of expression of selected cDNAs in response to cold. The results showed that subtractive hybridization is an efficient method for identification of cold-induced genes in plants with limited sequence information available. This study also revealed that genes induced during cold acclimation of the cold-hardy citrus relative P. trifoliata are similar to those in Arabidopsis, indicating that similar pathways may be present and activated during cold acclimation in woody perennial plants.


Assuntos
Citrus/genética , Regulação da Expressão Gênica de Plantas , Aclimatação , Citrus/classificação , Temperatura Baixa , Primers do DNA , DNA Complementar/genética , DNA de Plantas/genética , DNA de Plantas/isolamento & purificação , Reação em Cadeia da Polimerase , RNA de Plantas/genética , RNA de Plantas/isolamento & purificação , Sementes/genética , Sementes/fisiologia
14.
Funct Plant Biol ; 33(9): 863-875, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32689297

RESUMO

Poncirus trifoliata (L.) Raf. is a cold-hardy, interfertile Citrus relative able to tolerate temperatures as low as -26°C when cold acclimated. Therefore, it has been used for improving cold tolerance in cold-sensitive commercial citrus varieties. A cold-induced cDNA library was constructed by subtractive hybridisation of non-acclimated and 2-d cold-acclimated P. trifoliata seedlings and many genes induced in response to cold were identified. Two of these cDNAs, PI-B05 and PI-C10, were selected from this library for further characterisation. Full-length cDNA sequences of these genes were obtained by 5' and 3' rapid amplification of cDNA ends (RACE). Sequence analysis revealed that PI-B05 contained an apetala2 / ethylene response factor (AP2 / ERF) domain and showed homology with ERF proteins from other plants, some of which are involved in environmental stress-induced gene expression. PI-C10 contained both AP2 / ERF and B3 DNA binding domains and showed homology with other plant proteins in the RAV subfamily of the AP2 / ERF transcription factors, some of which are induced in response to cold and other environmental stresses. Expression patterns of these genes in cold-tolerant P. trifoliata and cold-sensitive pummelo [Citrus grandis (L.) Osb.] in response to cold and drought at different time points were analysed by northern blots. Expression analysis showed that both genes were induced in response to cold, but not under drought conditions in cold-hardy P. trifoliata. However, little or no expression of these genes was detected by northern analysis in cold-sensitive pummelo under cold or drought conditions. The sequence analysis and expression data indicated that these genes may play a role in cold-responsive gene expression in cold-hardy P. trifoliata and could possibly be used for improving cold tolerance in cold-sensitive citrus cultivars.

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