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General and comparative endocrinology2010; 167(1); 6-10; doi: 10.1016/j.ygcen.2010.02.022

Cloning, comparative sequence analysis and mRNA expression of calcium-transporting genes in horses.

Abstract: Epithelial calcium transport occurs by paracellular and transcellular mechanisms. Transcellular transport in intestinal and renal epithelia involves several transport proteins, including transient receptor potential vanilloid member 5 (TRPV5), member 6 (TRPV6), calbindin D9k (CB9), calbindin D28k (CB28), sodium calcium exchanger 1 (NCX1), plasma membrane calcium ATPase 1 (PMCA1), and the vitamin D receptor (VDR). We are interested in the horse because of its unique calcium physiology (high blood calcium, high intestinal calcium absorption, high renal excretion of calcium, low vitamin D concentrations), and because horses often have dysregulated calcium balance with various diseases. We cloned the mRNA for equine TRPV5, TRPV6, CB9, CB28, NCX1, PMCA1, and VDR, performed comparative mRNA and protein sequence analysis, and quantified their mRNA expression in the kidney and gastrointestinal tract. Sequence homology for the mRNAs and proteins was high among mammals (>75%), with fish having the lowest homology (<75%). TRPV5, TRPV6, and CB9 expression was higher in the duodenum and proximal jejunum and followed a similar expression pattern. CB28 expression was greatest in the kidney. PMCA1 and NCX1 expression was similar throughout the intestine, but in the kidney PMCA1 expression was higher. Based on our findings, the proximal small intestine is the main site for transcellular calcium transport, with TRPV6 and CB9 serving as the main transport proteins. In the kidney, TRPV6, CB28, and PMCA1 are likely more important. The low VDR expression in the equine small intestine and kidney relative to the large intestine, together with the reported high intestinal absorption and renal excretion of calcium, and low vitamin D concentrations suggests that epithelial calcium transport in horses is not as dependent on vitamin D as in other species.
Copyright 2010 Elsevier Inc. All rights reserved.
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Publication Date: 2010-03-11 PubMed ID: 20226785DOI: 10.1016/j.ygcen.2010.02.022Google 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.

This research study focuses on understanding calcium transport in horses by cloning, comparing, and analyzing mRNA expressions of specific calcium-transporting genes. Through this study, the researchers have identified that the proximal small intestine is pivotal for transcellular calcium transport with TRPV6 and CB9 as key transport proteins.

Understanding Calcium Transport

  • Calcium transport in the body primarily occurs through paracellular and transcellular mechanisms.
  • Transcellular transport specifically involves various proteins, including TRPV5, TRPV6, CB9, CB28, NCX1, PMCA1, and VDR.
  • In horses, the interest lies in it’s unique calcium physiology – high blood calcium, high absorption of calcium from the intestines, high excretion of calcium through the kidneys, and observed low vitamin D concentrations.

Methodology of the Study

  • The researchers cloned mRNA for the aforementioned proteins – TRPV5, TRPV6, CB9, CB28, NCX1, PMCA1, and VDR.
  • A comparative analysis was performed on mRNA and protein sequences for similarities.
  • Subsequently, the expression of these mRNA was quantified in the kidney and gastrointestinal tract of the horse.

Findings from the Study

  • The sequence homology was noted to be high among mammals (>75%), whereas it was significantly lower in fish (<75%).
  • The expression of TRPV5, TRPV6, and CB9 was seen to be higher in the duodenum and proximal jejunum, showing a similar expression pattern.
  • The expression of CB28 was found to be greater in the kidney.
  • The expression of PMCA1 and NCX1 was more or less similar throughout the intestine, but in the kidney, PMCA1 featured a high expression rate.

Conclusions from the Research

  • The researchers concluded that the primary site for transcellular calcium transport in horses is the proximal small intestine with TRPV6 and CB9 acting as major transport proteins.
  • In the kidney, the importance is likely placed on TRPV6, CB28, and PMCA1.
  • A lower expression of VDR in the horse’s small intestine and kidneys compared to the large intestine, coupled with high intestinal calcium absorption and renal calcium excretion and low vitamin D, suggest that epithelial calcium transport in horses may be less dependent on vitamin D than other species.

Cite This Article

APA
Rourke KM, Coe S, Kohn CW, Rosol TJ, Mendoza FJ, Toribio RE. (2010). Cloning, comparative sequence analysis and mRNA expression of calcium-transporting genes in horses. Gen Comp Endocrinol, 167(1), 6-10. https://doi.org/10.1016/j.ygcen.2010.02.022

Publication

General and comparative endocrinology
ISSN: 1095-6840
NlmUniqueID: 0370735
Country: United States
Language: English
Volume: 167
Issue: 1
Pages: 6-10

Researcher Affiliations

Rourke, K M
  • Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, 601 Vernon Tharp Street, Columbus, OH 43210, USA.
Coe, S
    Kohn, C W
      Rosol, T J
        Mendoza, F J
          Toribio, R E

            MeSH Terms

            • Animals
            • Calbindins
            • Cloning, Molecular
            • Horses
            • Plasma Membrane Calcium-Transporting ATPases / genetics
            • Polymerase Chain Reaction
            • RNA, Messenger / genetics
            • Receptors, Calcitriol / genetics
            • S100 Calcium Binding Protein G / genetics
            • Sequence Analysis, DNA
            • Sodium-Calcium Exchanger / genetics
            • TRPV Cation Channels / genetics

            Citations

            This article has been cited 11 times.
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              doi: 10.3390/ani13132145pubmed: 37443942google scholar: lookup
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              doi: 10.3390/metabo10090371pubmed: 32942601google scholar: lookup
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              doi: 10.3390/ijms17071095pubmed: 27409607google scholar: lookup
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