Multiple promoters regulate tissue‐specific alternative splicing of the human kallikrein gene, KLK11/hippostasin

Abstract

The human kallikrein (KLK) family consists of 15 genes located on human chromosome 19q13.4. KLK11/hippostasinis a member of the kallikrein family and is expressed in various tissues. Two types of KLK11 isoforms, isoform 1 and isoform 2, have been predicted from cDNA sequences. Isoform 1 has been isolated from human hippocampus, whereas isoform 2 has been isolated from prostate. However, the regulation and characteristics of these isoforms are unknown. We identified the first three exons (1a, 1b, and 1c) by determining their transcription initiation sites. Exon 1b contained the initiation codon of isoform 2, and noncoding exons 1a and 1c contributed to isoform 1 mRNA. The dual luciferase promoter assay revealed three promoter regions, corresponding to the first exon of each isoform. Reverse transcription and PCR showed that exon 1a was expressed in the hippocampus, thalamus, and non‐central nervous system (CNS) tissues, whereas exon 1b was detected only in non‐CNS tissues. Exon 1c was observed in both CNS and non‐CNS tissues, except for salivary glands. In vitro mutagenesis revealed that the initiation codon for isoform 2 in exon 1b was functional. Isoform 2 had additional hydrophilic amino acids at the amino terminal and was secreted from the neuroblastoma cell line Neuro2a. Isoform 1 fused with green fluorescent protein (GFP) was distributed to cellular processes, whereas isoform 2–GFP was retained in the Golgi apparatus. We suggest that not only alternative splicing but also tissue‐specific use of multiple promoters regulate the expression and intracellular trafficking of KLK11/hippostasin isoforms.

Identification and validation of Kallikrein‐ralated peptidase 11 as a novel prognostic marker of gastric cancer based on immunohistochemistry

“…Several other KLKs, for example, KLK5, 6, 7, 10, 11, and 14 are emerging biomarkers for ovarian cancer 32–34. The identification of KLK substrates and the development of proteolytic cascade models implicate KLK proteins in cancer progression 22, 35–37. Tissue‐specific expression patterns have been identified for KLKs members.…”

Identification of Alternative Transcripts Encoding the Essential Murine Gammaherpesvirus Lytic Transactivator RTA

“…Based on the current analyses, MHV68 RTA expression can be driven from four distinct promoters, and these promoters drive expression of 5 different spliced gene 50 transcripts. The identification of multiple promoters driving expression of a single gene is not a novel concept; there are many human and viral genes whose expression has been shown to be regulated by multiple promoters (38)(39)(40)(41)(42). For example, EBV has been shown to use differential splicing and from 2 distinct promoters in the generation of the transcripts encoding the six EBNA gene products (43)(44)(45)(46)(47).…”

Effects of the Demethylating Agent, 5-Azacytidine, on Expression of the Kallikrein-Kinin Genes in Carcinoma Cells of the Lung and Pleura

“…However in the present study, 5-AZA had no overall toxic effect on lung cancer or mesothelioma cells, as assessed by cell proliferation assays. It is also possible that decreased expression of some of the kallikrein-kinin genes after 5-AZA treatment may be due to the existence of multiple splice variants or the use of alternative promoters, as previously observed for KLK6 [37] and KLK11 [38]. …”