Comparison of the 5' upstream putative regulatory sequences of three members of the alpha2u-globulin gene family

Abstract

We have isolated and characterized seven members of the az,-globulin gene family from a rat genomic library. The 5' upstream region (up to 1250 base pairs starting from the EcoRI site in exon 2) of three clones was sequenced. The major transcriptional start points were located 25 base pairs downstream from the 'TATA' box. A very high degree of homology was observed over the entire studied region. Two of the examined genes displayed structural features which suggest that their expression may be impeded. A high degree of homology was observed between the promotor regions of a2,-globulin and those of the major urinary protein (MUP) multigene family of the mouse. A remarkable feature is the variable length of an A-rich region between the putative 'CAAT' and the 'TATA' consensus sequences. The size of this region differs markedly between MUP and a2,-globulin and between different members of the a2,-globulin gene family. Comparison of the a2,-globulin promotor with the corresponding region of other androgen-dependent genes (the C1, Cz and C3 subunits of prostatic steroid binding protein) reveals the presence of an A-rich region of homology located approximately 378 base pairs upstream from the cap site in the a,,-globulin genes. This region compares well with a sequence of putative enhancer function previously demonstrated in the a-fetoprotein promotor and in the immunoglobulin heavy chain promoter. a2,-Globulin is a protein of unknown function abundant in the urine of adult male rats but barely detectable in that of females. The majority of this protein is synthesized in the liver, secreted into the blood and, because of its small size (Mr = 18 700), excreted into the urine [l -31. The hepatic production of az,-globulin is under multihormonal control. Androgens are the most important physiological regulators but glucocorticoids, insulin, thyroxine and growth hormone are also required for normal synthesis [4-71. Oestrogens on the contrary [8, 91 and a factor secreted by ectopically transplanted pituitary glands [lo] suppress ~x~,-globulin. All these hormones control a2,-globulin synthesis mainly by regulating the hepatic level of a2,-globulin mRNA [ll-141. a2,-

Dynamic instability of the major urinary protein gene family revealed by genomic and phenotypic comparisons between C57 and 129 strain mice

“…The functional B6 gene 17 contains one notable difference: the presence of an extra 13 [A]s and a nearby C/A substitution within an A-rich site 30 bp upstream of the TATA-box element. We observe that similar (though non-identical) A-rich sites are present in the same location at each predicted Mup locus, and their presence and putative functionality have previously been highlighted in the equivalent rat gene family [ 44 , 45 ]. These elements do not appear to be protein binding sites.…”

Genomic organization of the rat α 2u -globulin gene cluster

“…The majority of ␣ 2u -globulin genes are likely to be functional, since only a single ␣ 2u -globulin pseudogene sequence has been reported (Winderickx et al 1987). The rat organization (lacking pairs of divergently oriented genes) is simpler and thus may more closely resemble the organization of the genes in the common ancestor of mice and rats.…”

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

“…The 40 base fragment evident in all lanes is the product of an unknown RNA crossing the transcription start site. It has been detected previously (Addison & Kurtz 1986) and may correspond to the transcript initiated 77 bp upstream of the one that gives rise to the 32 base protected fragment (Winderickx et al 1987).…”