Nomenclature

An ad hoc working group for expansin nomenclature reached concensus on a revision of expansin names and symbols in April 2004. Their recommendations were published in Plant Molecular Biology 55:311-314 and are briefly summarized as follows:

Only two-domain proteins will be designated as members of the expansin superfamily. The name "expansin" should not given to proteins that are homologous to only one of the expansin domains, i.e. the GH45-like domain I (SCOP 1.63 50685) and the grass pollen group-2 allergen-like domain II (SCOP 1.63 49590). The terms "g-expansin" and "d-expansin" should be abandoned.

To determine which family a gene belongs to, click here.

Accepted symbols for plant genes:

a-expansin (formerly EXP) becomes EXPA

b-expansin (formerly EXPB) remains EXPB

Expansin like (formerly EXPL) becomes EXLA (for expansin-like family A)

Expansin related (formerly EXPR) becomes EXLB (for expansin-like family B)

If any new gene families within this superfamily are discovered in plants, they will be given symbols EXLC, EXLD, after consultation with the working group.

The symbol EXLX (Expansin-like Group X) may be used to designate genes that fulfill these criteria:

	they are from organisms outside the plant world,
	they are homologous to expansins (that is, with homology to both domains)
	they do not fall within the established families

EXLX should not be interpreted to indicate a true (monophyletic) family, but rather it is a polyphyletic group, a catch-all group for expansin related sequences that do not fall into the recognized families.

Table 1. Revised names and symbols of expansin genes. ___________________________________________________________________________

Original name Former symbol^a New symbol New name

___________________________________________________________________________

α-Expansin EXP or EXPα1 EXPA EXPANSIN A

β-Expansin EXPB or EXPβ1 EXPB EXPANSIN B

Expansin-like EXPL or EXPβ2 EXLA EXPANSIN-LIKE A

Expansin-related EXPR or EXPβ3 EXLB EXPANSIN-LIKE B

Various EXP or none EXLX EXPANSIN-LIKE X

___________________________________________________________________________

Numbering should be in order of discovery, e.g. EXPA1, EXPA2, ...

Upper case, italicized symbols are used for gene names
Upper case, not italicized, symbols are used for proteins
Lower case, italicized symbols are used for mutant genes

The expansin working group consists of:

Hans Kende^1,*, Kent J. Bradford², David A. Brummell³, Hyung-Taeg Cho⁴, Daniel J. Cosgrove⁵, Andrew J. Fleming⁶, Chris Gehring⁷, Yi Lee⁸, Simon McQueen-Mason⁹, Jocelyn K.C. Rose¹⁰L.A.C.J. Voesenek¹¹

¹MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA (*author for correspondence; e-mail hkende@msu.edu); ²Seed Biotechnology Center, University of California, Davis CA 95616, USA; ³Crop and Food Research, Private Bag 11600, Palmerston North, 5301, New Zealand; ⁴School of Biosciences and Biotechnology, Chungnam National University, Daejeon 305-764, Republic of Korea; ⁵Department of Biology, 208 Mueller Laboratory, Pennsylvania State University, University Park, PA 16802, USA; ⁶Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK; ⁷University of the Western Cape, Department of Biotechnology, Private Bag X17, Bellville 7535, South Africa; ⁸Department of Tobacco Science, Chungbuk National University, 48 Gaesin-dong Hungduk-ku, Chongju 361-763, Republic of Korea; ⁹Biology Department, University of York, PO Box 373, York, YO10 5YW, UK; ¹⁰Department of Plant Biology, Cornell University, Ithaca, NY 14853, USA; ¹¹Plant Ecophysiology, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht, The Netherlands

This page was last updated on 03/22/06.

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