The S1fa transcription factor is part of a small family involved in plant growth and development and abiotic stress tolerance. The S1Fa protein was first isolated from a spinach cDNA expression library and was shown to exhibit tissue specific binding specificity to the negative rps1 cis element S1F (ATGGTAACAATT) binding site. Based on transient expression assay S1Fa represses the activity of rps1 encoding plastid ribosomal protein S1, and its expression is higher in roots and etiolated seedlings than in green leaves. It is highly conserved between monocotyledonous and dicotyledonous plants.

The structure of S1Fa is made up of hydrophilic N and C terminal domains having a potential to form a-helices and hydrophobic central domain to form b-sheets. The 12 residues of the second helix ISKKKMKRERLK forms a putative DNA recognition site (PF04689.16). The highly positive C-terminal domain contains a PPKKKK sequence suggesting its nuclear localization (Zhou et al., 1995). S1Fa like TF family belongs to the class of membrane bound transcription factors (MTFs) bound through transmembrane domains to the cellular membrane and upon proteolytic cleavage are released from the membrane and translocated to the nucleus to regulate gene expression (Yao et al., 2017).

S1Fa like TFs in Brassica napus leaves were upregulated at 1 h after salt stress, suggesting their role in regulating salt responsive target genes (Yong et al., 2014). In response to abiotic stress in cotton, S1Fa like TFs were one of the most abundant groups and most of the S1Fa like TFs were down regulated (Tahmasebi et al., 2019). Populus trichocarpa PtS1Fa1 and PtS1Fa2 expression is suppressed in response to drought and salt stress. However, overexpression of PtS1Fa2 but not PtS1Fa1 played a role in drought tolerance by upregulating gene expression of antioxidants superoxide dismutase (SOD) and peroxidase (POD) thereby reducing reactive oxygen species accumulation (ROS) (Zhao et al., 2021).

In peanut, (Arachis hypogaea L.), the S1Fa-like transcription factor family has 126 Arachis members, in contrast to no more than five members in other examined plant species, and is more highly expressed in roots and etiolated seedlings than green leaves. This expansion of some the S1Fa gene family suggests roles in the unusual subterranean fructification of Arachis (Chen et al., 2016).

Last updated June 2023 by Ankita Abnave

References:

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Yao S, Deng L, Zeng K. Genome-wide in silico identification of membrane-bound transcription factors in plant species. PeerJ. 2017 Nov 15;5:e4051. doi: 10.7717/peerj.4051. PMID: 29158982; PMCID: PMC5694209.

Yong HY, Zou Z, Kok EP, Kwan BH, Chow K, Nasu S, Nanzyo M, Kitashiba H, Nishio T. Comparative transcriptome analysis of leaves and roots in response to sudden increase in salinity in Brassica napus by RNA-seq. Biomed Res Int. 2014;2014:467395. doi: 10.1155/2014/467395. Epub 2014 Aug 7. PMID: 25177691; PMCID: PMC4142189.

Tahmasebi A, Ashrafi-Dehkordi E, Shahriari AG, Mazloomi SM, Ebrahimie E. Integrative meta-analysis of transcriptomic responses to abiotic stress in cotton. Prog Biophys Mol Biol. 2019 Sep;146:112-122. doi: 10.1016/j.pbiomolbio.2019.02.005. Epub 2019 Feb 22. PMID: 30802474.

Zhao H, Niu Y, Dong H, Jia Y, Wang Y. Characterization of the Function of Two S1Fa-Like Family Genes From Populus trichocarpa. Front Plant Sci. 2021 Oct 4;12:753099. doi: 10.3389/fpls.2021.753099. PMID: 34671378; PMCID: PMC8521066.

Chen X, Li H, Pandey MK, Yang Q, Wang X, Garg V, Li H, Chi X, Doddamani D, Hong Y, Upadhyaya H, Guo H, Khan AW, Zhu F, Zhang X, Pan L, Pierce GJ, Zhou G, Krishnamohan KA, Chen M, Zhong N, Agarwal G, Li S, Chitikineni A, Zhang GQ, Sharma S, Chen N, Liu H, Janila P, Li S, Wang M, Wang T, Sun J, Li X, Li C, Wang M, Yu L, Wen S, Singh S, Yang Z, Zhao J, Zhang C, Yu Y, Bi J, Zhang X, Liu ZJ, Paterson AH, Wang S, Liang X, Varshney RK, Yu S. Draft genome of the peanut A-genome progenitor (Arachis duranensis) provides insights into geocarpy, oil biosynthesis, and allergens. Proc Natl Acad Sci U S A. 2016 Jun 14;113(24):6785-90. doi: 10.1073/pnas.1600899113. Epub 2016 May 31. PMID: 27247390; PMCID: PMC4914189.