“Analysis of the regulation of the expression of Kv1.2 potassium channel”

Abstract

Neuron excitability is one of the most relevant functions in the nervous system and is controlled by voltage-gated ion channels. Voltage-gated potassium channels 1 (Kv1) are critical to maintaining membrane potential during resting. Also, Kv1 channels regulate the frequency, duration, and amplitude of action potentials, contributing to the membrane repolarization after the action potential firing. Alterations in the expression, function and subcellular distribution of neuronal Kv1.2 ion channels have been related to epilepsy and neuropathic pain. Even though Kv1.2 ion channels are one of the most characterized Kv1 channels, the regulation of their expression is poorly understood, and there are no transcription factors that regulate its expression. To determine the putative transcription factors that control the Kv1.2 gene (KCNA2) we did comparative analysis of its promoter region in KCNA2 orthologous. We selected a region of 1500 bp upstream transcription start site (TSS) and the 5 ́ untranslated region (UTR). To discover conserved regions with a regulatory function in the KCNA2 promoter through evolution, we analyzed the superorder of placental mammals called “Euarchontoglires”, which includes Primates, Dermoptera, Scandentia, Rodentia, and Lagomorpha with a more specific focus in species of Primates. We detected an increase in the repertoire of binding sites of transcription factors (TFBS) in the common ancestor of Catarrhini (14 sites), in the common ancestor of Hominoidea (22 sites) and in human (28 sites) KCNA2. By in silico analysis using the MAFFT alignment and transcription factor (TF) prediction tools, in the common ancestor of Euarchontoglires we observed four putative TFBS: a conserved site for Sp1 and AP-2, a site for

delta factor or Yin Yang 1 (YY1), a site for C/EBPα and a common site for NF-E2, AP-1 and Fra- l transcription factors.

Additionally, using the Phylogenetic Footprinting strategy, we detected ten structured phylogenetic variations in specific groups, such as Catarrhini, Anthropoidea, and Primates suggesting an additional transcriptional regulation through evolution. Among these variations, at 911 bp upstream the TSS we identify a site for YY1 transcription factors with an adjacent change of a T for a C in Catarrhini, which could affect the binding of YY1 to its site in the species belonging to this group. This work is the first study that identify possible transcription factors regulating KCNA2 expression. Therefore, additional investigations are necessary to probe these findings.