AUTHOR=Li Kunyu , Liu Yufang , He Xiaoyun , Tao Lin , Jiang Yanting , Lan Rong , Hong Qionghua , Chu Mingxing 

TITLE=A Novel SNP in the Promoter Region of IGF1 Associated With Yunshang Black Goat Kidding Number via Promoting Transcription Activity by SP1

JOURNAL=Frontiers in Cell and Developmental Biology

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2022.873095

DOI=10.3389/fcell.2022.873095

ISSN=2296-634X

ABSTRACT=<p><italic>IGF1</italic>, a member of the insulin-like growth factor (IGF) superfamily, is also known as the growth-promoting factor (somatomedin C). <italic>IGF1</italic> is involved in vertebrate growth and development, immunity, cell metabolism, reproduction, and breeding. However, there are relatively few studies on the relationship between <italic>IGF1</italic> and goat reproduction. In this study, a new transcription factor <italic>SP1</italic> bound to the <italic>IGF1</italic> g. 64943050T&gt;C promoted granulosa cell (GC) proliferation. A mutation g.64943050T&gt;C located in the promoter region of <italic>IGF1</italic> was identified. Association analysis revealed that the kidding number in the first and second litters and the average number of first three litters of the CC genotype (2.206 ± 0.044, 2.254 ± 0.056, and 2.251 ± 0.031) were significantly higher than those in the TC genotype (1.832 ± 0.049, 1.982 ± 0.06, and 1.921 ± 0.034) and TT genotype (1.860 ± 0.090, 1.968 ± 0.117, and 1.924 ± 0.062) (<italic>p</italic> &lt; 0.05). The kidding number in the third litter of the CC genotype (2.355 ± 0.057) was significantly higher than that in the TT genotype (2.000 ± 0.107) (<italic>p</italic> &lt; 0.05). Then, the function of this mutation was validated by the dual-luciferase reporter assay and EMSA. The results showed that the luciferase activity of IGF1-mutant-C was significantly higher than that of IGF1-Wild-T (<italic>p</italic> &lt; 0.05). The EMSA also showed that the binding ability of IGF1-mutant-C was higher than that of IGF1-Wild-T (<italic>p</italic> &lt; 0.05). Subsequently, the transcription factor <italic>SP1</italic> was predicted to bind to the mutation of <italic>IGF1</italic> (g.64943050T&gt;C). Overexpression of SP1 promotes the expression of <italic>IGF1</italic> in the primary granulosa cells (GCs). The results of the CCK-8 assay and the expression of GC proliferation factors (<italic>CDK4</italic>, <italic>cyclin D1</italic>, and <italic>cyclin D2</italic>) demonstrated that <italic>SP1</italic> promoted GC proliferation by regulating <italic>IGF1</italic> expression. Our results suggested that the <italic>IGF1</italic> g.64943050T&gt;C was significantly associated with the kidding number of Yunshang black goats, and <italic>SP1</italic> as a transcription factor of <italic>IGF1</italic> binding to the mutation T&gt;C regulated the expression of <italic>IGF1</italic>. Furthermore, <italic>SP1</italic> promoted goat GC proliferation by regulating the expression of <italic>IGF1</italic>, which provides a new insight for the goat fertility trait.</p>