Accession Number : ADA320044

Title :   Homeobox Genes and Patterning of the Proximal-Distal Axis in Regenerating Limbs.

Descriptive Note : Final rept. 1 Jun 92-31 May 96,

Corporate Author : CALIFORNIA UNIV IRVINE DEPT OF DEVELOPMENTAL AND CELL BIOLOGY

Personal Author(s) : Bryant, Susan V. ; Gardiner, David M.

PDF Url : ADA320044

Report Date : 31 MAY 1996

Pagination or Media Count : 6

Abstract : We have examined expression of HoxA genes, an of Msx-2 in developing and regenerating axolotl limbs, and in the developing lateral line system. We have found that Hox complex genes are regulated differently in limb development and regeneration. In development, Hoxa-9 and Hoxa-13 follow the rules of spatial and temporal colinearity seen in other developing limbs. However, in regeneration expression of both Hox genes occurs simultaneously and in the same physical location. The expression pattern is the same regardless of amputation level. Expression is initiated within a day of amputation, and the genes are expressed by the cells of the mature limb, days before these cells dedifferentiate to form a blastema. Spatially distinct domains of expression, identical to those in developing limbs, emerge during growth of the blastema. Factors from the wound epidermis may control reexpression of HoxA genes, and expression is affected in a position specific manner by retinoic acid. Finally, we have also studied the expression of Msx-2 in regenerating limbs and in the lateral line system. In regenerating limbs, Msx-2 is expressed prior to wound healing. In the lateral line system, Msx-2 is expressed continuously from placodal stages through to the mature neuromast.

Descriptors :   *MEDICAL SERVICES, *NERVES, *EPIDERMIS, *GROWTH(PHYSIOLOGY), POSITION(LOCATION), PATTERNS, DAY, GENES, WOUNDS AND INJURIES, HEALING, EXTREMITIES, REGENERATION(ENGINEERING), AMPUTATION.

Subject Categories : Anatomy and Physiology
      Medicine and Medical Research

Distribution Statement : APPROVED FOR PUBLIC RELEASE