caa a22 4500 397520735 CHVBK 20180308164631.0 cr unu---uuuuu 161202e199502 xx s 000 0 eng 10.1093/jxb/46.2.211 doi (NATIONALLICENCE)oxford-10.1093/jxb/46.2.211 Changes in ubiquitin and ubiquitin-protein conjugates during seed formation and germination [Elektronische Daten] [Ricardo Manuel Boavida Ferreira, Paula Cristina Rodrigues Ramos, Emanuel Franco, Cândido Pereira Pinto Ricardo, Artur Ricardo Nascimento Teixeira] Changes in both free ubiquitin and ubiquitin-protein conjugates were followed in cotyledons of lupin (Lupinus albus L.) during the course of seed formation, from the flower to the dry seed, and during germination and seedling growth, from the dry seed to the senescing cotyledons. The observed levels of ubiquitin conjugates, detected by immunoblotting using antiubiquitin antibodies and by autoradiography using 125I-labelled ubiquitin, suggest an intense involvement of the ubiquitin-mediated proteolytic pathway during the highly regulated phases of seed formation and germination. High amounts of free ubiquitin are present at all stages in all tissues examined. With the exception of the dry seed, the high molecular mass ubiquitin-protein conjugates are also present at all stages. Higher amounts of these conjugates were found during the initial stages of pod development and seed germination and during the most active phases of storage protein deposition and degradation. Germination and seedling growth in total darkness not only delays the degradation of the storage proteins, but also extends the period characterized by the presence of a high amount of these conjugates. No such conjugates were detected in the dry seeds, probably reflecting the extremely low metabolic activity observed in these organs. A number of smaller molecular mass polypeptides were also detected at different stages of seed development, germination and seedling growth. Of particular interest is the abrupt accumulation of an abundant 20 kDa polypeptide in the cotyledons during the 4th day after imbibition, which is maintained in high amounts in these organs, rapidly declining after about 12-14 d. The pattern of accumulation of the 20 kDa polypeptide is controlled neither by light nor by the embryo axes, and large variations in its concentration are observed during heat shock. © Oxford University Press Research Papers nationallicence Ubiquitin nationallicence ubiquitin-protein conjugates nationallicence seed storage proteins nationallicence protein synthesis nationallicence protein degradation nationallicence Ferreira Ricardo Manuel Boavida Instituto de Tecnologia Química e Biológica, Rua da Quinta Grande Apartado 127, 2780 Oeiras, Portugal aut Ramos Paula Cristina Rodrigues Instituto de Tecnologia Química e Biológica, Rua da Quinta Grande Apartado 127, 2780 Oeiras, Portugal aut Franco Emanuel Departamento de Botânica e Engenharia Biológica, Instituto Superior de Agronomia 1399 Lisboa Codex, Portugal aut Ricardo Cândido Pereira Pinto Instituto de Tecnologia Química e Biológica, Rua da Quinta Grande Apartado 127, 2780 Oeiras, Portugal aut Teixeira Artur Ricardo Nascimento Departamento de Botânica e Engenharia Biológica, Instituto Superior de Agronomia 1399 Lisboa Codex, Portugal aut Journal of Experimental Botany Oxford University Press 46/2(1995-02), 211-219 0022-0957 46:2<211 1995 46 exbotj https://doi.org/10.1093/jxb/46.2.211 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/jxb/46.2.211 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ferreira Ricardo Manuel Boavida Instituto de Tecnologia Química e Biológica, Rua da Quinta Grande Apartado 127, 2780 Oeiras, Portugal aut NATIONALLICENCE 700 1- Ramos Paula Cristina Rodrigues Instituto de Tecnologia Química e Biológica, Rua da Quinta Grande Apartado 127, 2780 Oeiras, Portugal aut NATIONALLICENCE 700 1- Franco Emanuel Departamento de Botânica e Engenharia Biológica, Instituto Superior de Agronomia 1399 Lisboa Codex, Portugal aut NATIONALLICENCE 700 1- Ricardo Cândido Pereira Pinto Instituto de Tecnologia Química e Biológica, Rua da Quinta Grande Apartado 127, 2780 Oeiras, Portugal aut NATIONALLICENCE 700 1- Teixeira Artur Ricardo Nascimento Departamento de Botânica e Engenharia Biológica, Instituto Superior de Agronomia 1399 Lisboa Codex, Portugal aut NATIONALLICENCE 773 0- Journal of Experimental Botany Oxford University Press 46/2(1995-02), 211-219 0022-0957 46:2<211 1995 46 exbotj Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford