Abstract
Cubilin, (CUBN; also known as intrinsic factor-cobalamin receptor [Homo sapiens Entrez Pubmed ref NM_001081.3; NG_008967.1;
GI: 119606627]), located in the epithelium of intestine and kidney acts as a receptor for intrinsic factor – vitamin B12 complexes.
Mutations in CUBN may play a role in autosomal recessive megaloblastic anemia. The current study investigated the possible role
of CUBN in evolution using phylogenetic testing. A total of 588 BLAST hits were found for the cubilin query sequence and these
hits showed putative conserved domain, CUB superfamily (as on 27
th
Nov 2012). A first-pass phylogenetic tree was constructed to
identify the taxa which most often contained the CUBN sequences. Following this, we narrowed down the search by manually
deleting sequences which were not CUBN. A repeat phylogenetic analysis of 25 taxa was performed using PhyML, RAxML and
TreeDyn softwares to confirm that CUBN is a conserved protein emphasizing its importance as an extracellular domain and being
present in proteins mostly known to be involved in development in many chordate taxa but not found in prokaryotes, plants and
yeast.. No horizontal gene transfers have been found between different taxa.