Echidna IgA supports mammalian unity and traditional Therian relationship

Echidna IgA supports mammalian unity and traditional Therian relationship IgA is found only in birds and mammals where it is the principal immunoglobulin class found in secretions, providing protection at mucosal surfaces. The structure of IgA in birds is different from that of marsupials and eutherians. The avian heavy-chain constant region of IgA (Ca) consists of four domains, while marsupial and eutherian Ca consists of three domains plus a hinge. Here we describe the cloning and characterization of the heavy chain of IgA from the short-beaked echidna, Tachyglossus aculeatus, and report that monotreme Ca is composed of three domains plus a hinge, making it similar to its therian counterparts. The amino acid sequence identity of echidna Ca is approximately 47% with the therians and 30% with birds. Phylogenetic analysis of the Ca sequences provides strong support for the Theria hypothesis, which proposes that monotremes diverged prior to the separation of marsupial and eutherians, and directly contradicts the results of the mitochondrial data, which support a "Marsupionta" relationship which has marsupials and monotremes closer to each other. The characterization of the heavy chain of IgA from monotremes, in conjunction with the recent description of monotreme IgG and IgE nucleotide sequence, confirms that the 'second big bang' of immunoglobulin evolution predated the divergence of extant mammals. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Mammalian Genome Springer Journals

Echidna IgA supports mammalian unity and traditional Therian relationship

Loading next page...
 
/lp/springer_journal/echidna-iga-supports-mammalian-unity-and-traditional-therian-H5tfDpNSlO
Publisher
Springer-Verlag
Copyright
Copyright © 2002 by Springer-Verlag New York Inc.
Subject
Life Sciences; Cell Biology; Animal Genetics and Genomics; Human Genetics
ISSN
0938-8990
eISSN
1432-1777
D.O.I.
10.1007/s00335-002-3004-7
Publisher site
See Article on Publisher Site

Abstract

IgA is found only in birds and mammals where it is the principal immunoglobulin class found in secretions, providing protection at mucosal surfaces. The structure of IgA in birds is different from that of marsupials and eutherians. The avian heavy-chain constant region of IgA (Ca) consists of four domains, while marsupial and eutherian Ca consists of three domains plus a hinge. Here we describe the cloning and characterization of the heavy chain of IgA from the short-beaked echidna, Tachyglossus aculeatus, and report that monotreme Ca is composed of three domains plus a hinge, making it similar to its therian counterparts. The amino acid sequence identity of echidna Ca is approximately 47% with the therians and 30% with birds. Phylogenetic analysis of the Ca sequences provides strong support for the Theria hypothesis, which proposes that monotremes diverged prior to the separation of marsupial and eutherians, and directly contradicts the results of the mitochondrial data, which support a "Marsupionta" relationship which has marsupials and monotremes closer to each other. The characterization of the heavy chain of IgA from monotremes, in conjunction with the recent description of monotreme IgG and IgE nucleotide sequence, confirms that the 'second big bang' of immunoglobulin evolution predated the divergence of extant mammals.

Journal

Mammalian GenomeSpringer Journals

Published: Nov 1, 2002

There are no references for this article.

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off