Gecko CD59 Is Implicated in Proximodistal Identity during Tail Regeneration

Several adult reptiles, such as Gekko japonicus, have the ability to precisely re-create a missing tail after amputation. To ascertain the associated acquisition of positional information from blastemal cells and the underlying molecular mechanism of tail regeneration, a candidate molecule CD59 was isolated from gecko. CD59 transcripts displayed a graded expression in the adult gecko spinal cord with the highest level in the anterior segment, with a stable expression along the normal tail. After tail amputation, CD59 transcripts in the spinal cord proximal to the injury sites increased markedly at 1 day and 2 weeks; whereas in the regenerating blastema, strong CD59 positive signals were detected in the blastemal cells anterior to the blastema, with a gradual decrease along the proximodistal (PD) axis. When treated with RA following amputation, CD59 transcripts in the blastema were up-regulated. PD confrontation assays revealed that the proximal blastema engulfed the distal one after in vitro culture, and rabbit-anti human CD59 antibody was able to block this PD engulfment. Overexpression of the CD59 during tail regeneration causes distal blastemal cells to translocate to a more proximal location. Our results suggest that position identity is not restricted to amphibian limb regeneration, but has already been established in tail blastema of reptiles. The CD59, a cell surface molecule, acted as a determinant of proximal–distal cell identity

Inclusive particle production in pp interactions at 12 and 24 GeV/c I The central region

The authors present double-differential cross sections for the central region in the reactions p+p to pi /sup +or-/+anything at incident laboratory momenta of 12 and 24 GeV/c, and compare them with CERN-ISR measurements at higher momenta. They find remarkable regularities when they express these cross sections as functions of y*, p/sub T/, and s. The use of the c.m. longitudinal rapidity y*=sinh/sup -1/(p*/sub ////(p/sup 2//sub T/+m/sup 2/)/sup 1/2/) (where p*/sub /// and p/sub T / are the longitudinal and transverse c.m. momenta), instead of the more conventional variable x=p*/sub ////( square root s/2), is crucial because these regularities in the central region are not evident in the variables x and p/sub T/. (12 refs)