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Home / Equine Research Bank / Theriogenology / The recombinant equine LHβ subunit combines divergent ...
Theriogenology2015; 83(9); 1469-1476; doi: 10.1016/j.theriogenology.2015.01.026

The recombinant equine LHβ subunit combines divergent intracellular traits of human LHβ and CGβ subunits.

Abstract: The pituitary LHβ and placental CGβ subunits are products of different genes in primates. The major structural difference between the two subunits is in the carboxy-terminal region, where the short carboxyl sequence of hLHβ is replaced by a longer O-glycosylated carboxy-terminal peptide in hCGβ. In association with this structural deviation, there are marked differences in the secretion kinetics and polarized routing of the two subunits. In equids, however, the CGβ and LHβ subunits are products of the same gene expressed in the placenta and pituitary (LHβ), and both contain a carboxy-terminal peptide. This unusual expression pattern intrigued us and led to our study of eLHβ subunit secretion by transfected Chinese hamster ovary and Madin-Darby canine kidney cells. In continuous labeling and pulse-chase experiments, the secretion of the eLHβ subunit from the transfected Chinese hamster ovary cells was inefficient (medium recovery of 16%-25%) and slow (t1/2 > 6.5 hours). This indicated that, the secretion of the eLHβ subunit resembles that of hLHβ rather than hCGβ. In Madin-Darby canine kidney cells grown on Transwell filters, the eLHβ subunit was preferentially secreted from the apical side, similar to the hCGβ subunit secretory route (∼65% of the total protein secreted). Taken together, these data suggested that secretion of the eLHβ subunit integrates features of both hLHβ and hCGβ subunits. We propose that the evolution of this intracellular behavior may fulfill the physiological demands for biosynthesis of the LH and CG β-subunits in the pituitary and placenta, respectively.
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Publication Date: 2015-01-29 PubMed ID: 25796287PubMed Central: PMC5603182DOI: 10.1016/j.theriogenology.2015.01.026Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research involves the study of the secretion behavior of the recombinant equine LHβ subunit, a genetically distinct hormone subunit found in horses. This subunit shares both similarities and differences with the LHβ and CGβ subunits in humans, leading researchers to investigate how this might impact its function.

Genetic Background and Objectives

  • The hormone beta-subunits LHβ and CGβ in humans are produced by separate genes, with each having distinguishable features, particularly in the carboxy-terminal region.
  • LHβ and CGβ subunits in equids, including horses, are products of one gene, both containing a carboxy-terminal peptide. This unusual genetic expression intrigued scientists and prompted this experimental exploration.

Methodology

  • The research team used Chinese hamster ovary cells and Madin-Darby canine kidney cells, transfected with the recombinant equine LHβ subunit, to study its secretion.
  • The secretion of the eLHβ was analyzed based on its efficiency, speed (using continuous labeling and pulse-chase experiments), and the route of secretion.

Findings of the Study

  • The results showed low efficiency (16%-25%) and slow secretion (t1/2 > 6.5 hours) from the transfected Chinese hamster ovary cells, indicating similarity with the secretion of the human LHβ subunit.
  • In Madin-Darby canine kidney cells, however, the eLHβ subunit was mostly secreted from the apical side (~65% of the total protein secreted), which is consistent with the human CGβ subunit secretory route.
  • These results demonstrate that the secretion of the eLHβ subunit display traits of both human subunits.

Conclusions and Implications

  • Based on the findings, the researchers concluded that the secretion of the eLHβ subunit may have evolved to meet the physiological needs for biosynthesis of the LH and CG β-subunits in the pituitary and placenta respectively.
  • This study provides valuable insights into the understanding of the unique genetic and secretion properties of the eLHβ subunit in equids, which will potentially contribute to further research in reproductive biology.

Cite This Article

APA
Cohen L, Bousfield GR, Ben-Menahem D. (2015). The recombinant equine LHβ subunit combines divergent intracellular traits of human LHβ and CGβ subunits. Theriogenology, 83(9), 1469-1476. https://doi.org/10.1016/j.theriogenology.2015.01.026

Publication

Theriogenology
ISSN: 1879-3231
NlmUniqueID: 0421510
Country: United States
Language: English
Volume: 83
Issue: 9
Pages: 1469-1476
PII: S0093-691X(15)00043-6

Researcher Affiliations

Cohen, Limor
  • Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, Israel.
Bousfield, George R
  • Department of Biological Sciences, Wichita State University, Wichita, Kansas, USA.
Ben-Menahem, David
  • Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, Israel. Electronic address: dbm@bgu.ac.il.

MeSH Terms

  • Amino Acid Sequence
  • Animals
  • CHO Cells
  • Chorionic Gonadotropin, beta Subunit, Human / chemistry
  • Chorionic Gonadotropin, beta Subunit, Human / genetics
  • Chorionic Gonadotropin, beta Subunit, Human / physiology
  • Cricetinae
  • Cricetulus
  • Dogs
  • Evolution, Molecular
  • Female
  • Horses / genetics
  • Humans
  • Luteinizing Hormone / chemistry
  • Luteinizing Hormone / genetics
  • Luteinizing Hormone / physiology
  • Madin Darby Canine Kidney Cells
  • Molecular Sequence Data
  • Protein Subunits / chemistry
  • Protein Subunits / genetics
  • Protein Subunits / physiology
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Sequence Alignment

Grant Funding

  • P01 AG029531 / NIA NIH HHS

Conflict of Interest Statement

The authors declare no conflict of interest

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Citations

This article has been cited 2 times.
  1. Byambaragchaa M, Lee SY, Kim DJ, Kang MH, Min KS. Signal Transduction of Eel Luteinizing Hormone Receptor (eelLHR) and Follicle Stimulating Hormone Receptor (eelFSHR) by Recombinant Equine Chorionic Gonadotropin (rec-eCG) and Native eCG.. Dev Reprod 2018 Mar;22(1):55-64.
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  2. Park JJ, Seong HK, Kim JS, Munkhzaya B, Kang MH, Min KS. Internalization of Rat FSH and LH/CG Receptors by rec-eCG in CHO-K1 Cells.. Dev Reprod 2017 Jun;21(2):111-120.
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