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L C Snyder

Publications and source records attributed to L C Snyder.

7 recordsLinked to original sources

Distortion of transmission ratio by a candidate t complex responder locus transgene.

The mouse t complex responder locus (Tcr) is centrally involved in the phenomenon of male-specific transmission ratio distortion (TRD) through its action in haploid germ cells. Previously, we identified a candidate gene, Tcp-10b, whose t allele generates alternatively spliced transcripts. The full-length Tcp-10bt transcript is present in pre- and postmeiotic germ cells and encodes a product that is virtually identical with that encoded by the wild-type allele. The alternatively spliced t-specific transcript is observed in post-meiotic haploid spermatids and would encode an altered polypeptide that could convey the Tcrt phenotype. To assess their function, we have introduced constructs representing each Tcp-10bt transcript into transgenic mice. Breeding experiments demonstrate that these two constructs alter the transmission ratios of t haplotypes from male mice, but in opposite directions. The results provide support for the hypothesis that Tcp-10bt is a component of the Tcr locus.

Animals↗

Allele- and haploid-specific product generated by alternative splicing from a mouse t complex responder locus candidate.

Mouse t haplotypes represent a variant form of chromosome 17 that has evolved the ability to propagate through natural populations by the phenomenon of 'transmission ratio distortion' (TRD), in which heterozygous +/t males transmit their t-carrying chromosome to 95% or more of their offspring. Although multiple t-associated loci have a role in expression of this phenotype, only one--the t complex responder (Tcr) locus--is responsible for determining which of the two homologues of chromosome 17 will be transmitted at a high ratio. A candidate gene (Tcp-10b) for Tcr that is expressed in both meiotic and post-meiotic male germ cells has been cloned. But for this candidate gene to function as the haploid effector of TRD, the t-allele of this gene (Tcp-10bt) must express a unique product in a haploid-specific manner. Here we show that a change in the splicing pattern of Tcp-10bt transcripts occurs during sperm differentiation. This change results in a unique allele-specific and haploid-specific transcript which could encode a variant polypeptide that would fulfil the conditions required of the Tcr effector of TRD.

Alleles↗

A gene amplified in a transformed mouse cell line undergoes complex transcriptional processing and encodes a nuclear protein.

We have explored the structure and pattern of expression of a gene designated mdm-1, which is amplified 25-30-fold in transformed mouse cells containing numerous double minute particles. This gene is expressed in all mouse tissues examined but exhibits elevated and altered patterns of expression in the testis. Multiple transcripts are generated from the mdm-1 gene via mechanisms of alternative splicing and polyadenylation signal choice. These mRNAs have the potential to produce a minimum of three distinct protein products ranging in size from 25 to 77 kilodaltons. Antiserum generated against a synthetic peptide from the mdm-1 gene was used in immunoblotting studies and revealed that at least one of the protein products is present in the nucleus. This antiserum stained nuclear structures producing a distinct punctate or speckled pattern.

Animals↗