Unusual gene order and organization of the sea urchin hox cluster.
While the highly consistent gene order and axial colinear patterns of expression seem to be a feature of vertebrate hox gene clusters, this pattern may be less well conserved across the rest of the bilaterians. We report the first deuterostome instance of an intact hox cluster with a unique gene order where the paralog groups are not expressed in a sequential manner. The finished sequence from BAC clones from the genome of the sea urchin, Strongylocentrotus purpuratus, reveals a gene order wherein the anterior genes (Hox1, Hox2 and Hox3) lie nearest the posterior genes in the cluster such that the most 3' gene is Hox5. (The gene order is 5'-Hox1, 2, 3, 11/13c, 11/13b, 11/13a, 9/10, 8, 7, 6, 5-3'.) The finished sequence result is corroborated by restriction mapping evidence and BAC-end scaffold analyses. Comparisons with a putative ancestral deuterostome Hox gene cluster suggest that the rearrangements leading to the sea urchin gene order were many and complex.
Cameron
R Andrew
RA
Division of Biology and the Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA. acameron@caltech.edu
Rowen
Lee
L
Nesbitt
Ryan
R
Bloom
Scott
S
Rast
Jonathan P
JP
Berney
Kevin
K
Arenas-Mena
Cesar
C
Martinez
Pedro
P
Lucas
Susan
S
Richardson
Paul M
PM
Davidson
Eric H
EH
Peterson
Kevin J
KJ
Hood
Leroy
L
D000818:Animals; D001483:Base Sequence; D022202:Chromosomes, Artificial, Bacterial; D015870:Gene Expression; D023061:Gene Order; D005801:Genes, Homeobox / Q000235:genetics*; D035683:MicroRNAs / Q000235:genetics; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D047270:Strongylocentrotus purpuratus / Q000235:genetics*
D035683:MicroRNAs