Abstract. We have studied the expression of the human SRY protein (termed p27SRY) in two different cell lines by using specific antibodies. Confocal microscopy enabled us to localize p27SRY precisely in the nucleus in a discrete punctuate pattern. Furthermore, through microinjection experiments, we have demonstrated that the localization of the p27SRY protein into the nucleus was an event involving the NH2-terminal part of the high mobility group (HMG) domain. With the help of several synthetic peptides and various p27SRY mutants, we have characterized a bipartite basic motif in this part of the protein corresponding to a nuclear localization signal. This nuclear localization signal appears to be highly conserved in SRY box-and HMB box-containing proteins, suggesting common properties of nuclear targeting within the HMG box protein family.

Teneurin‐2 is a member of a novel family of transmembrane proteins characterized to date in fish, birds, mammals, and Drosophila (e.g., the pair‐rule gene product Ten‐m). We have shown that teneurin‐2 is expressed by neurons in the developing avian visual system in a pattern complementary to the expression of teneurin‐1 and that recombinant teneurin‐2 induces morphologic changes in neuronal cells in culture (Rubin et al., 1999). Here we have used cRNA probes to two newly identified splice variants and a teneurin‐2‐specific antibody to determine whether teneurin‐2 is also expressed outside the nervous system. Both reverse transcriptase‐polymerase chain reaction and in situ hybridization indicate that the three splice variants known so far are coexpressed at sites of pattern formation during development. Teneurin‐2 mRNAs and protein are found in the developing limbs, somites, and craniofacial mesenchyme. In addition to expression of teneurin‐2 by the apical ectodermal ridge, teneurin‐2 transcripts also appear transiently at sites of tendon development. Teneurin‐2 expression patterns were strikingly similar to those of fibroblast growth factor 8 (FGF8). In agreement with the overlapping expression pattern, FGF8‐coated beads implanted into chicken limb buds induced the ectopic expression of teneurin‐2 and soluble FGF8 induced teneurin‐2 in limb explant cultures. Thus, teneurin‐2 could act downstream of FGF8 during morphogenesis. © 2001 Wiley‐Liss, Inc.