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161.
Anne Schoendorf Roberte Bronner Jean Broadhvest François Bernier 《Sexual plant reproduction》1998,11(3):140-147
In the tobacco (Nicotiana tabacum) Appendix mutant, anthers are tipped by a miniature style and stigma. The outgrowth appears on the anther when it is already
differentiating and follows the developmental timing of the central carpel. The Appendix mutation thus represents a late homeotic
transformation suggesting that the APPENDIX (APX) gene either could be a misregulated organ identity gene or could be involved in regulating the expression of such genes.
RFLP analysis with two class B (TM6 and NTGLO) and a class C (NAG) probes revealed that the Appendix phenotype is not caused by a mutation in one of these genes. However, in situ hybridization
showed important changes in the expression of NTGLO and NAG in the mutant when compared with wild-type tobacco. Surprisingly, although no phenotypic alteration other than the style
and stigma outgrowth is observed in the Appendix mutant, changes in class B and class C gene expession were not restricted
to the anther tip cells from which the outgrowth originates. As expected, NAG was expressed in the Appendix outgrowth but it was also overexpressed in the normal third and fourth whorl organs at the
time the outgrowth, as well as the central styles and stigmas, differentiated. Overexpression of a class C gene is probably
responsible for the Appendix phenotype. In normal and mutant flowers, NTGLO was expressed in the second, third and fourth whorls up to the time of carpel fusion. Expression of this class B gene then
ceased in the fourth whorl organs but was reactivated at later stages only in the styles and stigmas as well as in the outgrowths
of the mutant. It thus seems that the function of the APX gene is either to regulate the late expression of organ identity genes or to control cell proliferation in such a way that,
in the mutant, some cells are in a state where they respond in an unusual way to developmental signals.
Received: 17 October 1997 / Revision accepted: 24 March 1998 相似文献
162.
Summary Three patients with mental retardation and multiple congenital abnormalities are described.Although their clinical appearance was not suggestive of Down's syndrome, chromosome studies showed a non-disjunctional trisomy 21 in two of the patients. The third case had an unsuspected XXY karyotype. 相似文献
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Chen H Hayashi G Lai OY Dilthey A Kuebler PJ Wong TV Martin MP Fernandez Vina MA McVean G Wabl M Leslie KS Maurer T Martin JN Deeks SG Carrington M Bowcock AM Nixon DF Liao W 《PLoS genetics》2012,8(2):e1002514
An important paradigm in evolutionary genetics is that of a delicate balance between genetic variants that favorably boost host control of infection but which may unfavorably increase susceptibility to autoimmune disease. Here, we investigated whether patients with psoriasis, a common immune-mediated disease of the skin, are enriched for genetic variants that limit the ability of HIV-1 virus to replicate after infection. We analyzed the HLA class I and class II alleles of 1,727 Caucasian psoriasis cases and 3,581 controls and found that psoriasis patients are significantly more likely than controls to have gene variants that are protective against HIV-1 disease. This includes several HLA class I alleles associated with HIV-1 control; amino acid residues at HLA-B positions 67, 70, and 97 that mediate HIV-1 peptide binding; and the deletion polymorphism rs67384697 associated with high surface expression of HLA-C. We also found that the compound genotype KIR3DS1 plus HLA-B Bw4-80I, which respectively encode a natural killer cell activating receptor and its putative ligand, significantly increased psoriasis susceptibility. This compound genotype has also been associated with delay of progression to AIDS. Together, our results suggest that genetic variants that contribute to anti-viral immunity may predispose to the development of psoriasis. 相似文献
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Karelle Benardais Basem Kasem Alice Couegnas Brigitte Samama Sebastien Fernandez Christiane Schaeffer Maria-Cristina Antal Didier Job Annie Schweitzer Annie Andrieux Anne Giersch Astrid Nehlig Nelly Boehm 《PloS one》2010,5(9)