A second expressed kininogen gene in mice

Abstract

. A second expressed kininogen gene in mice. Physiol Genomics 26: 152-157, 2006; doi:10.1152/physiolgenomics.00244.2005.-We isolated PCR, RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE-PCR)-, and RT-PCR-generated clones from mouse kininogen family transcripts. DNA sequencing indicated that the clones were from two distinct genes. One set (K1) is from the previously reported mouse kininogen gene. The second set (K2) has an open reading frame, is 93% identical to K1 in the overlapping nucleotide sequence, and, unlike T-kininogens in the rat, encodes a bradykinin motif identical to K1. We discovered that K2 exists with two different 5Ј ends. We used RT-PCR to determine the distribution and relative abundance of K1 and K2 mRNA in mouse tissues. K2 is transcribed and K1 and K2 are generally both expressed in the same tissues; however, they differ in their regulation of the alternative splicing event that yields either low-molecular-weight kininogen (LMWK) or high-molecular-weight kininogen (HMWK). For example, in the liver K1 is expressed as both HMWK and LMWK, whereas K2 is only expressed as LMWK. Conversely, in the kidney K2 is strongly expressed as both HMWK and LMWK, whereas K1 is not expressed as HMWK and expressed only very weakly as LMWK.polymerase chain reaction; DNA sequencing; alternative splicing KININOGENS ARE PROTEIN SUBSTRATES for tissue and plasma kallikrein. When cleaved, they release kinin peptides that function as vasodilators and are involved in the cardioprotective effect of angiotensin-converting enzyme inhibitors. Mammals produce two types of kininogens, termed high-molecular-weight kininogen (HMWK) and low-molecular-weight kininogen (LMWK). Both HMWK and LMWK mRNA are encoded by the same gene via 1) alternative RNA splicing in exon 10 and 2) the use of different polyadenylation sites, resulting in the generation of two distinct types of kininogen mRNA.Bovine, human, rat, and mouse LMWK and HMWK cDNAs have been cloned and sequenced (4, 5, 9). The sequences of the two additional kininogen family genes unique to rats, called T-kininogens, have also been determined (2). T-kininogens exist only as LMWK; they are not substrates for tissue and plasma kallikrein and do not have a standard bradykinin motif, but rather T-kinin (Ile-Ser-bradykinin). In addition, T-kininogens have a remnant noncoding DNA sequence that is homologous to the exon 10 HMWK-specific region of rat kininogen.Previously, only a single kininogen gene has been identified in all species studied except for rats. Although a previous report indicated that mice likely have only a single kininogen gene (10), we (3) and others (1) have reported the discovery of a second expressed kininogen family gene in this species. Here we further examine this second kininogen gene's sequence and expression. METHODSInitial generation of mouse HMWK-specific PCR fragments. PCR primers specific to the mouse kininogen exon 10 HMWK region (primer set A) were chosen by homology among rat, mouse, and human HMWK DNA; where they differed, the mou...

Deletion of murine kininogen gene 1 (mKng1) causes loss of plasma kininogen and delays thrombosis

“…Our results are consistent with these findings, though Shesely et al did not assess the roles of the 2 kininogen genes in production of kininogen protein. 31 In our studies, deletion of mKng1 was confirmed by demonstrating the absence of mKng1-derived mRNA in tissues in which the gene is normally expressed (Figure 5). Deletion of this gene allowed us to analyze the contribution of the 2 kininogen genes to the production of plasma kininogen.…”

“…31 These investigators reported mKng1-derived HK and LK mRNA and mKng2-derived LK mRNA in the liver, and mKng1-derived LK and mKng2-derived For personal use only. on June 19, 2019.…”

The kallikrein–kinin system in health and in diseases of the kidney

“…Humans have one kininogen gene; rodents have two closely linked kininogen genes. 22 Kallidin can be converted into bradykinin by a plasma aminopeptidase. All the kinins are strong agonists of the bradykinin 2 receptor (B2R, Bdkrb2), although less so of the B1 receptor (B1R, Bdkrb1).…”