title: An exceptionally long CA-repeat in the core promoter of SCGB2B2 links with the evolution of apes and Old World monkeys.
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.
authors.affiliation: Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Nikkhah
authors.affiliation: Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Rezazadeh
authors.affiliation: Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: H R
authors.initials: HR
authors.lastname: Khorram Khorshid
authors.affiliation: Department of Biostatistics, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: A
authors.initials: A
authors.lastname: Biglarian
authors.affiliation: Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. Electronic address: ohadi.mina@yahoo.com.
authors.forename: M
authors.initials: M
authors.lastname: Ohadi
mesh_terms: D000818:Animals; D002520:Cercopithecidae / Q000235:genetics*; D018900:Dinucleotide Repeats; D019143:Evolution, Molecular; D015186:Hominidae / Q000235:genetics*; D006801:Humans; D011401:Promoter Regions, Genetic; D060765:Secretoglobins / Q000235:genetics*
chemical_list: D060765:Secretoglobins
keywords: Ape; CA-repeat; Evolution; Old World monkey; SCGB2B2