AN OCTAMER ELEMENT IS REQUIRED FOR THE EXPRESSION OF THE ALPHA-H2B HISTONE GENE DURING THE EARLY DEVELOPMENT OF THE SEA-URCHIN

被引:24
作者
BELL, J
CHAR, BR
MAXSON, R
机构
[1] UNIV SO CALIF, SCH MED, DEPT BIOCHEM, 1441 EASTLAKE AVE, LOS ANGELES, CA 90033 USA
[2] UNIV SO CALIF, KENNETH R NORRIS HOSP & INST, SCH MED, LOS ANGELES, CA 90033 USA
关键词
D O I
10.1016/0012-1606(92)90248-F
中图分类号
Q [生物科学];
学科分类号
07 ; 0710 ; 09 ;
摘要
Early (alpha) histone genes are one of several histone gene families in the sea urchin genome. They are expressed at high levels in blastula-stage embryos and are inactivated by the early gastrula stage. By microinjecting mutant early H2B genes into sea urchin zygotes and monitoring their transcriptional activity in blastula- and gastrula-stage embryos, we sought to identify the cis-regulatory elements responsible for this dramatic change in early H2B gene activity. We found that deletion of DNA 5′ of -71 and 3′ of +591 did not affect the timing or magnitude of early H2B gene expression. Neither was early H2B gene expression affected by the replacement of sequences downstream of -36 with the corresponding region of the L1 late H2B gene, expressed after the peak transcription of the early H2B gene. Further deletion of early H2B promoter sequences from -71 to -56, removing a conserved octamer element, resulted in near-complete inactivation of the early H2B gene in both blastula- and gastrula-stage embryos. Also inactivating early H2B gene expression were an internal deletion of the octamer element and a base substitution mutation that altered its sequence. This base substitution mutation also caused a parallel reduction in the ability of the octamer element to bind a factor present in nuclear extracts of sea urchin blastulae. These data strongly suggest that the proper expression of the early H2B gene in cleavage- and blastula-stage embryos depends on the octamer element and a factor with which it interacts. © 1992.
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页码:363 / 371
页数:9
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