International Mammalian Genome Society

The 15th International Mouse Genome Conference (2001)

Table of Contents * Complex Genetics * Developmental Genetics * Gene Annotation * Gene Discovery * Genome Sequencing * Functional Genomics * Mutagenesis * Presentations * Verne Chapman Memorial Lecture

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POSTER 90 - GENOME  ANALYSIS OF CRITICAL REGION OF A MOUSE PREAXIAL POLYDACTYLY MUTATION, HEMIMELIC EXTRA TOES (HX) (Hx)

Dr Tomoko Sagai
Mammal. Genet. Natl. Inst. Genet.
1111 Yata
Mishima 411-8540
Japan

Co-Authors: 1) Masuya H, 2) Shimizu K, 3) Yada Y, 4) Tamura M, 5) Shiroishi T
Institutions: 1)Riken Gsc, 2)Nihon University, 3)Ochanomizu University, 4)Kyoto University, 5) Mammalian Genetics Natl.Inst.Genet.

Preaxial polydactyly of mouse hemimelia luxate member is associated with an ectopic expression of Shh in the anterior limb mesenchyme. Little is known for the molecular mechanism of such a misregulation of shh. One of the member, hemimelic extra-toes (Hx) is a dominant mutation characterized by preaxial polydactyly and shortening of the radius, tibia and talus. Hx has been mapped to the extreme vicinity of shh. Recently, Lmbr1 encoding a novel transmembrane receptor, has been served as a possible candidate of Hx. Lmbr1 is a mouse homolog of C7orf2, which was identified as a candidate of the limb deformity mapped in the human syntenic region, 7q36. Although Lmbr1/C7orf2 has been reported to have a role in the limb development, no mutation that causes preaxial polydactyly has been identified both in human and mouse. In this study, we constructed precise genetic and physical maps and localized Lmbr1 in the critical region. This study, however, did not reveal any mutation in the Lmbr1coding region of Hx mutant. Furthermore, we did not detect large alteration of the Lmbr1 expression level in the developing limb buds of Hx homozygote. Therefore, it is still circumstantial that Lmbr1 is the direct causative gene for Hx.