| First Author | Shawlot W | Year | 1998 |
| Journal | Transgenic Res | Volume | 7 |
| Issue | 2 | Pages | 95-103 |
| PubMed ID | 9608737 | Mgi Jnum | J:46634 |
| Mgi Id | MGI:1201712 | Doi | 10.1023/a:1008816308171 |
| Citation | Shawlot W, et al. (1998) Restricted beta-galactosidase expression of a hygromycin-lacZ gene targeted to the beta-actin locus and embryonic lethality of beta-actin mutant mice. Transgenic Res 7(2):95-103 |
| abstractText | beta-actin is a cytoskeletal protein that is ubiquitously expressed. To exploit the regulation the beta-actin gene, a promoterless hygromycin-lacZ fusion gene with a splice acceptor was introduced into the first intron of the beta-actin locus by homologous recombination in mouse embryonic stem (ES) cells. The targeted ES cells were hygromycin resistant and expressed beta-galactosidase (beta-gal) activity. However, no beta-gal activity was detected in heterozygous embryos. In adult heterozygotes, beta-gal activity was detected only in testes. RT-PCR analysis demonstrated the presence of both beta-actin exon 1-hygromycin- and exon l-exon 2-containing transcripts in homozygous mutant embryos. LacZ-containing transcripts were detected in adult heterozygous tests and, surprisingly, in homozygous mutant embryos. These results demonstrate that the integration of the hygromycin-lacZ gene into the first intron of the beta-actin locus was not productive for the ubiquitous expression of beta-gal activity. Because this integration mimics certain types of gene trap events, it suggests that caution should be used when interpreting beta-gal expression patterns in genetic screens using gene trap strategies. In addition, mice homozygous for the beta-actin mutation developed normally up to embryonic day 8.5 (E8.5) but became growth retarded at E9.5 and subsequently died. The RT-PCR data indicate that this targeted mutation is a hypomorphic allele of beta-actin. |
