Bhargav S. Arimilli, Phillips Exeter Academy BrownID: 140003669 Functional Description of Cyclin Family Proteins Bhargav S. Arimilli 1 , Dr. Matyas Cserhati, Ph.D. 2 , and Dr. Chittibabu Guda, Ph.D. 2 1 Phillips Exeter Academy, Exeter, NH, USA 2 The University of Nebraska Medical Center, Omaha, NE, USA Abstract The cyclin family of proteins is important in regulating the different stages of the cell cycle by activating cyclin-dependent kinases (CDKs). This study aims to be a functional characterization of the set of genes that are related to the cyclin A1-1 gene found in Arabidopsis thaliana. Introduction Cyclins are a family of proteins that regulate various stages of the eukaryotic cell cycle by activating cyclin-dependent kinases (CDKs). A cyclin protein will form a complex with a CDK, which causes phosphorylation of the substrate, which results in orderly progression through the cell cycle. This study was comprised of four components: finding homologues of cyclin A1,1 in other species, retrieving protein sequences of such homologues and comparing their conserved domains, retrieving the promoter sequence for each protein, and identifying protein motifs in each protein. Materials and Methods The cyclin A1,1 gene was run under the Basic Local Alignment Search Tool (BLAST) to search for homologous genes in other species. Next, the protein encoded by the cyclin A1,1 gene was also run under the BLAST program to search for similar proteins in other organisms. The results of this search are shown in Table 1. The four similar species found, in addition to Arabidopsis thaliana, were Theobroma cacao (cocoa tree), Ricinus communis (castor oil plant), Populus trichocarpa (black cottonwood tree), and Glycine max (soybean). Table 1: Cyclin Family Proteins Protein ID RNA ID Name Species XP_002306649 XM_002306613 Cyclin family protein Populus trichocarpa XP_007019158 XM_007019095 Cyclin A1,1 isoform 2 Theobroma cacao XP_002520329 XM_002520283 Cyclin A, putative Ricinus communis NP_001237800 NM_001250871 Mitotic cyclin a2-type Glycine max NP_175077 NM_103537 Cyclin-A1-1 Arabidopsis thaliana