Publications of NIPGR Scientists
Permanent URI for this communityhttps://ndkr-library.nipgr.ac.in/handle/123456789/1
Browse
2 results
Search Results
Item The Mediator subunit OsMED15a is a transcriptional co-regulator of seed size/weight-modulating genes in rice(Elsevier B.V., 2019) Dwivedi, Nidhi; Maji, Sourobh; Waseem, Mohd; Thakur, Pallabi; Kumar, Vinay; Parida, Swarup K.; Thakur, Jitendra K.Although several transcription factors (TFs) that regulate seed size/weight in plants are known, the molecular landscape regulating this important trait is unclear. Here, we report that a Mediator subunit, OsMED15a, links rice grain size/weight-regulating TFs to their target genes. Expression analysis and high-resolution quantitative trait loci (QTL) mapping suggested that OsMED15a is involved in rice seed development. OsMED15a has an N-terminal, three-helical KIX domain. Two of these helices, α1 and α3, and three amino acids, 76LRC78, within OsMED15a helix α3 were important for its interaction with several proteins, including interactions with the transactivation domains of two NAC-type TFs, OsNAC024 and OsNAC025. Moreover, OsMED15a, OsNAC024, and OsNAC025 all exhibited increased expression during seed development, and we identified several grain size/weight-associated SNPs in these genes in 509 low- and high-grain-weight rice genotypes. RNAi-mediated repression of OsMED15a expression down-regulated the expression of the grain size/weight regulating genes GW2, GW5 and DR11 and reduced grain length, weight, and yield. Of note, both OsNAC024 and OsNAC025 bound to the promoters of these three genes. We conclude that the transactivation domains of OsNAC024 and OsNAC025 target the KIX domain of OsMED15a in the regulation of grain size/weight-associated genes such as GW2, GW5, and D11. We propose that the integrated molecular-genetics approach used here could help identify networks of functional alleles of other regulator and co-regulator genes and thereby inform efforts for marker-assisted introgression of useful alleles in rice crop improvement.Item KIX domain of AtMed15a, a Mediator subunit of Arabidopsis, is required for its interaction with different proteins(Taylor & Francis Group, 2018) Kumar, Vinay; Waseem, Mohd; Dwivedi, Nidhi; Maji, Sourobh; Kumar, Angad; Thakur, Jitendra K.Med15 is an important subunit of Mediator tail module and is characterized by a KIX domain present in the amino terminal. In yeast and metazoans, Med15 KIX domain has been found to interact with various transcription factors, regulating several processes including carbohydrate metabolism, lipogenesis, stress response and multidrug resistance. Mechanism of Med15 functioning in Arabidopsis is largely unknown. In this study, interactome of Arabidopsis Med15, AtMed15a, was characterized. We found 45 proteins that interact with AtMed15a KIX domain, including 11 transcription factors, 3 single strand nucleic acid-binding proteins and 1 splicing factor. The third helix of the KIX domain was found to be involved in most of the interactions. Mapping of the regions participating in the interactions revealed that the activation domain of a transcription factor, UKTF1 interacted with AtMed15a KIX domain. Thus, our results suggest that in Arabidopsis, activation domain of transcription factors target KIX domain of AtMed15a for their transcriptional responses.