Hβ58, and insertional mutation affecting early postimplantation development of the mouse embryo

G. Radice, J. J. Lee, F. Costantini

Research output: Contribution to journalArticle

49 Scopus citations

Abstract

The generation and analysis of insertional mutations affecting mouse embryogenesis provides a powerful method to identify new genes that function in early development. In this paper, we describe an insertional mutation that interferes with postimplantation mouse development beginning at the time of gastrulation. Embryos homozygous for the Hβ58 transgenic insertion developed normally through the early postimplantation, egg cylinder stage (day 6.5 of development). At the primitive streak stage (day 7.5), however, they began to display characteristic abnormalities, including a retardation in the growth of the embryonic ectoderm (the earliest identifiable defect), and in some cases abnormalities of the amnion and chorion. Homozygotes continued to develop for 2-3 more days, reaching the size of a normal 8.5 day embryo, and formed tissues representative of all three germ layers, including several differentiated cell types. The site of insertion was mapped, by a combination of cytogenetic and genetic methods, to chromosome 10, and it appeared to define a new genetic locus. The inserted transgene provided a probe to clone and characterize the mutant locus, as well as the corresponding wild-type locus. In addition to an insertion of 10-20 copies of the transgene, the mutant locus contained a deletion of 2-3 kb of DNA found at the wild-type locus, and possibly an insertion of mouse repetitive DNA. However, genomic sequences on both sides of the insertion siteremained co-linear in the wildtype and mutant genomes, and no chromosomal abnormalities d be detected. Five single copy DNA probes spanning the insertion site were tested for their ability to hybridize to RNA from 8.5 day embryos; one of the probes (located within the region deleted from the mutant chromosome) hybridized to a 2.7 kb mRNA encoded at the Hβ58 locus, thus identifying a gene whose disruption appears to be responsible for the mutant phenotype.

Original languageEnglish (US)
Pages (from-to)801-811
Number of pages11
JournalDevelopment
Volume111
Issue number3
StatePublished - Apr 4 1991

Keywords

  • Hβ58
  • insertional mutation
  • mouse embryo
  • postimplantation development

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology

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