scholarly journals Heterogeneity of high-mobility-group protein 2. Enrichment of a rapidly migrating form in testis

1985 ◽  
Vol 229 (1) ◽  
pp. 233-240 ◽  
Author(s):  
L R Bucci ◽  
W A Brock ◽  
M L Meistrich

A determination of the absolute amounts of high-mobility-group proteins 1 and 2 (HMG1 and HMG2) in rat tissues demonstrated that amounts of HMG2 were low in non-proliferating tissues, somewhat higher in proliferating and lymphoid tissues, but were extremely elevated in the testis. This increase was due to a germ-cell-specific form of HMG2 with increased mobility relative to somatic HMG2 on acid/urea/polyacrylamide-gel electrophoresis. To determine if the findings in the rat were a general feature of spermatogenesis, testis (germinal), spleen (lymphoid), and liver (non-proliferating) tissues from various vertebrate species were examined for their relative amounts of HMG1 and HMG2, and for HMG2 heterogeneity. Bull, chimpanzee, cynomologus monkey, dog, gopher, guinea pig, hamster, mouse, opossum, rabbit, rat, rhesus monkey, squirrel and toad (Xenopus) tissues were analysed. Nearly all species showed relatively high contents of HMG2 in testis tissue, whereas HMG1 contents were similar in all species and tissues. Ten of thirteen species showed a rapidly migrating HMG2 subtype in testis tissue, separable by acid/urea/polyacrylamide-gel electrophoresis. Xenopus, which lacks HMG2 in somatic tissues, showed an HMG2-like protein in testis tissue. Although the rapidly migrating HMG2 subtype in species other than rat was not testis-specific, it was always enriched in the testis. This study indicates that increased amounts of HMG2 and the enrichment of a rapidly migrating HMG2 subtype are general features of spermatogenic cells.

1984 ◽  
Vol 259 (14) ◽  
pp. 8840-8846
Author(s):  
L R Bucci ◽  
W A Brock ◽  
I L Goldknopf ◽  
M L Meistrich

2007 ◽  
Vol 73 (1) ◽  
pp. 260-269 ◽  
Author(s):  
Natalia Krynetskaia ◽  
Hongbo Xie ◽  
Slobodan Vucetic ◽  
Zoran Obradovic ◽  
Evgeny Krynetskiy

1998 ◽  
Vol 12 (5) ◽  
pp. 664-674 ◽  
Author(s):  
Lorene E. Romine ◽  
Jennifer R. Wood ◽  
LuAnne A. Lamia ◽  
Paul Prendergast ◽  
Dean P. Edwards ◽  
...  

Abstract We have examined the ability of the high-mobility group protein 1 (HMG1) to alter binding of the estrogen receptor DNA-binding domain (DBD) to the estrogen response element (ERE). HMG1 dramatically enhanced binding of purified, bacterially expressed DBD to the consensus vitellogenin A2 ERE in a dose-dependent manner. The ability of HMG1 to stabilize the DBD-ERE complex resulted in part from a decrease in the dissociation rate of the DBD from the ERE. Antibody supershift experiments demonstrated that HMG1 was also capable of forming a ternary complex with the ERE-bound DBD in the presence of HMG1-specific antibody. HMG1 did not substantially affect DBD-ERE contacts as assessed by methylation interference assays, nor did it alter the ability of the DBD to induce distortion in ERE-containing DNA fragments. Because HMG1 dramatically enhanced estrogen receptor DBD binding to the ERE, and the DBD is the most highly conserved region among the nuclear receptor superfamily members, HMG1 may function to enhance binding of other nuclear receptors to their respective response elements and act in concert with coactivator proteins to regulate expression of hormone-responsive genes.


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