EHD1 - An EH-domain-containing protein with a specific expression pattern

A cDNA that is a member of the eps15 homology (EH)-domain-containing family and is expressed differentially in testis was isolated from mouse and huma n. The corresponding genes map to the centromeric region of mouse chromosom e 19 and to the region of conserved synteny on human chromosome 11q13. Nort hern analysis revealed two RNA species in mouse. In addition to the high le vels in testis, expression was noted in kidney, heart, intestine, and brain . In human, three RNA species were evident. The smaller one was predominant in testis, while the largest species was evident in other tissues as well. The predicted protein sequence has an EH domain at its C-terminus, includi ng an EF, a Ca2+ binding motif, and a central coiled-coil structure, as wel l, as a nucleotide binding consensus site at its N-terminus. As such, it is a member of the EH-domain-containing protein family and was designated EHD 1 (EH domain-containing 1). In cells in tissue culture, we localized EHD1 a s a green fluorescent protein fusion protein, in transferrin-containing, en docytic vesicles, Immunostaining of different adult mouse organs revealed m ajor expression of EHD1 in germ cells in meiosis, in the testes, in adipocy tes,and in specific retinal layers. Results of ia situ hybridization to who le embryos and immunohistochemical analyses indicated that EHD1 expression was already noted at day 9.5 in the limb buds and pharyngeal arches-and at day 10.5 in sclerotomes, at various elements of the branchial apparatus (ma ndible and hyoid), and in the occipital region. At day 15.5 ERD1 expression peaked in cartilage, preceding hypertrophy and ossification, and at day 17 .5 there was no expression in the bones. The EHD1 gene is highly con-served between nematode, Drosophila, mouse, and human. Its predicted protein stru cture and cellular localization point to the possibility that EHD1 particip ates in ligand-induced endocytosis. (C) 1999 Academic Press.