The Primate-specific Express Genes Tcp10l The Functional Studies

The thesis includes two sections, in which we report the functional analysis of the primate-specific expression gene TCP10L in the first section and the cloning and characterization of a novel human SPRYD4 gene encoding a putative SPRY domain-containing protein in the second section.In the first section it is firstly indentified that TCP10L is derived through segmental duplication since the divergence of primates and rodents, and to be a primate-specific gene. The newly created TCP10L formed homodimerization through the previously identified putative leucine zipper motif. When overexpressed in SMMC7721 cell, both the ratio of cells in S phase and the cell colony formation rate increased. However, when TCP10L was silenced with RNAi in SMMC7721 cell, the above phenomenon was dismissed. In this study, the interaction between TCP10L and Nek6/Nek7 were also confirmed. It was identified that TCP10L may function as the substrate of Nek6/Nek7 and its stability may be regulated by Nek6/Nek7. TCP10L may also have roles in the negative feedback control of Nek6/Nek7, since it could regulate the activity of Nek6/Nek7 through affecting phosphorylation on Thr210 and Thr190 in Nek6 and Nek7, respectively.In the second section of this thesis, we report the cloning and characterization of a novel human SPRYD4 gene which encodes a SPRY domain-containing protein. The SPRYD4 gene was isolated from human brain cDNA library, and mapped to 12q13.2 by searching the UCSC genomic database. The SPRYD4 cDNA is 1201 base pairs in length and contains an open reading frame encoding 207 amino acids. The SPRYD4 gene consisted of 2 exons and encodes a putative protein with a SPRY domain ranging from amino acid residues 86 to 203. RT-PCR analysis revealed that SPRYD4 was expressed ubiquitously in 18 human tissues. However, it was strongly expressed in kidney, bladder, brain, thymus and stomach, while weakly expressed in liver, testis, uterus, spleen and lung. Subcellular localization demonstrated that SPRYD4 protein was localized in the nuclei when overexpressed in COS-7 cells.In conclusion, we first proposed the identification of TCP10L to be a primate-specific gene and its function in regulating cell cycle through interaction with Nek6/Nek7, which help us to learn well about the mechanism of cell cycle regulation, and we cloned a novel human SPRY domain containing gene.