Case Control Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Diabetes. Mar 15, 2019; 10(3): 181-188
Published online Mar 15, 2019. doi: 10.4239/wjd.v10.i3.181
Screening the RFX6-DNA binding domain for potential genetic variants in patients with type 2 diabetes
Ismail S Mahmoud, Ayat Homsi, Hamzeh J Al-Ameer, Jihad Alzyoud, Mais Darras, Mohammad Al Shhab, Malek Zihlif, Ma’mon M Hatmal, Walhan Alshaer
Ismail S Mahmoud, Jihad Alzyoud, Mais Darras, Ma’mon M Hatmal, Department of Medical Laboratory Sciences, Faculty of Allied Health Sciences, The Hashemite University, Zarqa 13133, Jordan
Ayat Homsi, Walhan Alshaer, Cell Therapy Centre, The University of Jordan, Amman 11942, Jordan
Hamzeh J Al-Ameer, Mohammad Al Shhab, Malek Zihlif, Department of Pharmacology, Faculty of Medicine, The University of Jordan, Amman 11942, Jordan
Author contributions: Mahmoud IS designed the study; Al-Ameer HJ and Darras M collected patient sample and data; Mahmoud IS, Al-Ameer HJ, Homsi A and Shhab MA made the lab experiment; Alzyoud J and Mahmoud IS analysed statistical data; Alshaer W, Zihlif M and Hatmal MM made contribution of new reagents or analytical tools; Mahmoud IS prepared the manuscript.
Institutional review board statement: The study was ethically approved by the IRB board of Jordan University Hospital (JUH) No. 10-2017-1737, Decision No. 2017-134. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee as well as the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent statement: Informed consents were obtained from human participants in this research.
Conflict-of-interest statement: The authors declare no conflict of interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Ismail Sami Mahmoud, PhD, Doctor, researcher and lecturer, Department of Medical Laboratory Sciences, Faculty of Allied Health Sciences, The Hashemite University, Zarqa 13133, Jordan. ismails@hu.edu.jo
Telephone: +96-279-7545880
Received: February 6, 2019
Peer-review started: February 10, 2019
First decision: February 19, 2019
Revised: March 8, 2019
Accepted: March 11, 2019
Article in press: March 11, 2019
Published online: March 15, 2019
ARTICLE HIGHLIGHTS
Research background

Diabetes mellitus is a global health challenge, which is usually associated with the loss/dysfunction of insulin-producing pancreatic beta cells. Hence, understanding the molecular mechanisms that control beta cells differentiation and function represents a major interest in the medical field. Regulatory factor X6 (RFX6) is DNA binding protein that is predominantly expressed in pancreatic islets of human and plays a key role in regulating pancreatic beta cells differentiation and insulin production, and it has been recently. RFX6 contains a highly conserved DNA binding domain which is critical for binding of RFX6 to DNA and consequently regulates the amount of messenger RNA produced by the gene. Several lines of evidence have indicated that RFX6 binding to DNA could be disrupted in diabetes. However, the mechanism by which this could happen is still unknown.

Research motivation

The presence of genetic mutations in the gene coding for the RFX6-DNA binding domain could result in inhibition of binding of RFX6 to DNA and consequently loss of function. Defining such genetic mutations will provide valuable information to diagnose, treat, prevent and cure type 2 diabetes (T2D).

Research objectives

In this study, we sought to investigate if any structural genetic mutations could be present in the RFX6-DNA binding domain in T2D patients and whether they are associated with diabetes.

Research methods

A case-control study was conducted in T2D patients and healthy volunteers. The DNA was extracted from all subjects and polymerase chain reaction (PCR) was used to amplify genomic DNA encompassing the coding sequences and intronic borders of exons 3, 4, 5 and 6 of the RFX6 gene, then PCR samples were analysed by DNA sequencing.

Research results

Our data showed the absence of any mutation in the exons coding for the RFX6-DNA binding domain. However, we have identified a new heterozygous single nucleotide polymorphism (IVS6+31 C>T) in the intronic region of DNA binding domain gene that is present in 9.2% and 8.5% of diabetic and control people, respectively (P = 0.97).

Research conclusions

We conclude that genetic mutations in the DNA binding domain of RFX6 are unlikely to exist in T2D.

Research perspectives

RFX6 binding to DNA is mediated by multiple of domains. Indeed, RFX6 proteins contain other conserved regions, including B, C, and D domains, which play a critical role in oligomerization of the protein and are required for DNA binding and activation. Thus, testing the other functional domains of RFX6 in future will provide more insights into the role of RFX6 in diabetes.