Nikkhah M, Rezazadeh M, Khorram Khorshid HR, Biglarian A, Ohadi M. An exceptionally long
CA-repeat in the core promoter of SCGB2B2 links with the evolution of apes and Old World monkeys.
Gene 2015;
576:109-14. [PMID:
26437309 DOI:
10.1016/j.gene.2015.09.070]
[Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 09/25/2015] [Accepted: 09/28/2015] [Indexed: 12/31/2022]
Abstract
We have recently reported a genome-scale catalog of human protein-coding genes that contain "exceptionally long" STRs (≥6-repeats) in their core promoter, which may be of selective advantage in this species. At the top of that list, SCGB2B2 (also known as SCGBL), contains one of the longest CA-repeat STRs identified in a human gene core promoter, at 25-repeats. In the study reported here, we analyzed the conservation status of this CA-STR across evolution. The functional implication of this STR to alter gene expression activity was also analyzed in the HEK-293 cell line. We report that the SCGB2B2 core promoter CA-repeat reaches exceptional lengths, ranging from 9- to 25-repeats, across Apes (Hominoids) and the Old World monkeys (CA>2-repeats were not detected in any other species). The longest CA-repeats and highest identity in the SCGB2B2 protein sequence were observed between human and bonobo. A trend for increased gene expression activity was observed from the shorter to the longer CA-repeats (p<0.009), and the CA-repeat increased gene expression activity, per se (p<0.02). We propose that the SCGB2B2 gene core promoter CA-repeat functions as an expression code for the evolution of Apes and the Old World monkeys.
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