Three subsets of genes whose tissue specific expression is sex and age‐dependent can be identified within the rat α2u‐globulin family

Abstract

The rat alpha 2u-globulins are encoded by a multigene family whose 20-25 members are subjected to multihormonal regulation that is dependent upon the sex of the animal, the developmental stage and the tissue being examined. Using RT-PCR and diagnostic restriction analysis of the products, we have examined the specificity of the expression of different members of the gene family. All family members can be classified into three subsets, depending on how the amplified cDNA responds to digestion with ApaLI, SstI and VspI. Subset A contains the restriction sites for both ApaLI and SstI but not VspI and typifies the genes expressed in the salivary glands of both mature and juvenile animals of both sexes, where it is the only subset expressed. This subset of genes also accounts for all the transcripts observed in the kidneys and mammary glands of juvenile males. Although subset A was represented in the transcript populations of all the other tissues examined, its proportion relative to the total varied greatly. The two other subsets were subset V, which contains only the restriction site for VspI, and subset N, which lacks all three restriction sites. In all the other tissues examined, two or all three of the subsets were expressed, usually in a manner that was unique to the sex and age of the tissue in question. The proportion of each of the three alpha 2u-globulin subsets in the alpha 2u-globulin gene family was determined by quantitation of the restriction products of amplified genomic DNA. Interestingly, the most prevalent subset in the genome (N) has the most limited tissue expression pattern, but is found in liver and preputial glands, the tissues expressing the most substantial quantities of alpha 2u-globulin. These results indicate the complexity of the regulation of the alpha 2u-globulins and point to the necessity for gene specific analyses if the expression of the family is to be understood in molecular terms.

The induction by estrogen of rat alpha 2u-globulin gene expression in mouse L-cells

“…1 show that clone 91 belongs to the class of 2u -globulin genes designated as N (Wang et al 1997). The tissues in which these genes are predominantly expressed are those of the liver and the preputial gland (Wang et al 1997). Gene expression in the former is clearly under multihormonal control which is consistent with the responsiveness of clone 91 to both estrogen (this study) and dexamethasone (Kurtz 1981b).…”

“…The data of Fig. 1 show that clone 91 belongs to the class of 2u -globulin genes designated as N (Wang et al 1997). The tissues in which these genes are predominantly expressed are those of the liver and the preputial gland (Wang et al 1997).…”

“…The data in Fig. 1 show that clone 91 belongs to class N whose amplified cDNA is not cut by any of the three enzymes used in this analysis (Wang et al 1997). The liver sample also contains transcripts from this same class N, as may be judged from the failure of the triple digest to cleave all of the uncut 312 bp product (Fig.…”

“…Reverse transcription, the subsequent amplification by PCR and diagnostic restriction digestion of the products were carried out as previously described (Wang et al 1997).…”

“…We have been able to distinguish three classes of transcript for the 2u -globulin family that are tissue-specific in their distribution (Wang et al 1997). To assign the specific member of the gene family used in our studies, clone 91 (Kurtz 1981b), to one of these classes, we subjected amplified cDNA from L-cells carrying plasmid 91R91 to diagnostic restriction analysis.…”