Abstract
The expression of LDH-C (Lactate dehydrogenase C) gene is restricted in mature germ cells; however multiple splice variants of LDH-C expressed in human cancers and yak normal testes were reported recently. In order to know if there are any LDH-C splice variants in human normal testes, we set out to clone the putative variants in human and rat. Four splicing variants in human testes, 1 splicing variant in human spermatozoa, 6 splicing variants in rat testes and 1 splicing variant in rat non-testes tissues (liver, heart and muscle) were cloned. The putative polypeptides encoded by these variants were compared with the full-length LDH-C protein, the results showed that these putative polypeptides were truncated LDH-C proteins or truncated LDH-C proteins with a few amino acid residues different at N or C terminal. This suggested that these variants are possibly not used for translation, but targets of nonsense-mediated mRNA decay. Western blotting did not detect any bands with similar molecular weight as the putative polypeptides. RT-PCR showed that the expression levels of the splicing variants were significant during development of rat testes. The results indicate that LDH-C was not silenced by transcriptional repression in non-mature germ cells, but significantly transcripted and alternatively spliced.
Highlights
Mammalian Lactate dehydrogenase (LDH; EC1.1.1.27) protein family is a kind of tetrameric NAD+-specific dehydrogenases and serves as the terminal enzyme of glycolysis, catalyzing reversible oxidation-reduction reaction between pyruvate and lactate (Everse and Kaplan, 1973)
LDH-A is most active in skeletal muscle and other tissues where oxygen deficiency happens frequently and glycolysis is required to satisfy metabolic needs, while LDH-B is abundantly expressed in cardiac muscle and liver that is dependent upon aerobic metabolism pathways
The results indicate that LDH-C was not silenced by transcriptional repression in non-mature germ cells, but significantly transcripted and alternatively spliced
Summary
Mammalian Lactate dehydrogenase (LDH; EC1.1.1.27) protein family is a kind of tetrameric NAD+-specific dehydrogenases and serves as the terminal enzyme of glycolysis, catalyzing reversible oxidation-reduction reaction between pyruvate and lactate (Everse and Kaplan, 1973). Sci., 5(4): 182-189, 2013 variants in virtually all tumor types they tested (Koslowski et al, 2002) They discovered the aberrant splicing patterns of LDH-C restricted to tumor cells and expression of LDH-C in tumors is neither mediated by gene promotor demethylation, as previously described for other germ cell-specific genes activated in cancer, nor induced by hypoxia as demonstrated for enzymes of the glycolytic pathway. The author, estimated the specific expression pattern may have something to do with the unique energy metabolism of cancer cells and LDH-C activation in cancer may provide a metabolic rescue pathway in tumor cells by exploiting lactate for ATP delivery He and colleagues reported that LDH-C multiple splicing variants were detected in some mammals’ testes (He et al, 2008; Huang et al, 2012). The results indicate that LDH-C was not silenced by transcriptional repression in non-mature germ cells, but significantly transcripted and alternatively spliced
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
