P-Locus Is a Target for the Melanogenic Effects of MC-1R Signaling

Abstract The pattern of transposition of Ac from the mutable allele bz-m2(Ac) has been investigated. Stable (bz-s) and finely spotted (bz-m(F)) exceptions were selected from coarsely spotted bz-m2(Ac) ears. The presence or absence of a transposed Ac (trAc) in the genome was determined and, when present, the location of the trAc was mapped relative to the flanking markers sh and wx. The salient general features of Ac transposition to sites linked to bz are that the receptor sites tend to be clustered on either side of the bz donor site and that transposition is bidirectional and nonpolar. Thus, the symmetrical clustering in the distribution of receptor sites adjacent to bz differs from the asymmetrical clustering reported in 1984 for the P locus by I. M. GREENBLATT. Though Ac tends to transpose preferentially to closely linked sites, an appreciable fraction of Ac transpositions from bz-m2(Ac) is to unlinked sites: 41% among bz-s derivatives and 59% among bz-m(F) derivatives. Many transposition events among the bz-m(F) selections result in kernels carrying a genetically noncorresponding embryo. These can be interpreted as twin sectors arising at one of the megagametophytic mitoses. The bz locus data fit the earlier (1962) model of I. M. GREENBLATT and R. A. BRINK in which transposition takes place from a replicated donor site to either an unreplicated or replicated receptor site.

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Gene expression at the pink-eyed dilution (p) locus in the mouse is confirmed to be pigment cell autonomous using recombinant embryonic skin grafts

Development ◽

10.1242/dev.87.1.65 ◽

1985 ◽

Vol 87 (1) ◽

pp. 65-73

Author(s):

Dennis A. Stephenson ◽

Janet E. Hornby

Keyword(s):

Gene Expression ◽

Environmental Influence ◽

Pigment Cell ◽

Epistatic Effect ◽

Skin Grafts ◽

Experimental Systems ◽

Grafting Technique ◽

Embryonic Skin ◽

Pink Eyed Dilution ◽

P Locus

Sash (Wsh), a viable and fully fertile allele of the dominant spotting (W) locus (Lyon & Glenister, 1982) has been expression at the pink-eyed dilution (p) locus. Reciprocal recombinant epidermal//dermal skin grafts were constructed from 13-day embryonic skin of p and Wsh homozygotes. Thus in the reciprocal experiments pink-eyed dilution melanocytes were exposed to any environmental influence from the wild-type allele of thep locus in either the epidermis (when WshWsh) or the dermis (when WshWsh). The hair pigmentation of the grafts recovered after three weeks beneath the testicular tunica of adult male mice was always typical of the p phenotype showing thatp is melanocyte autonomous. This result was supported by experiments using a modification of Mayer's (1965) neural crest grafting technique and the construction of 14-day recombinant skin grafts. Sash (WshWsh) epidermis can support melanocyte differentiation and pigment production but lacks functional melanocytes. The advantages of Wsh in experimental systems for testing the site of pigment gene expression have been demonstrated. Control experiments confirmed the dermal influence of agouti (A) over non-agouti (a) epidermis but non-agouti dermis did not overrule agouti pink-eyed dilution (AA pp) epidermis suggesting an epistatic effect ofp in the melanocyte.

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A New Spontaneous Allele at the Pink-Eyed Dilution (p) Locus Discovered in Mus musculus castaneus.

Experimental Animals ◽

10.1538/expanim.44.347 ◽

1995 ◽

Vol 44 (4) ◽

pp. 347-351 ◽

Cited By ~ 2

Author(s):

Atsushi TSUJI ◽

Takao WAKAYAMA ◽

Akira ISHIKAWA

Keyword(s):

Mus Musculus ◽

Pink Eyed Dilution ◽

P Locus

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Genetic and molecular analysis of recessive alleles at the pink-eyed dilution (p) locus of the mouse.

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.89.15.6968 ◽

1992 ◽

Vol 89 (15) ◽

pp. 6968-6972 ◽

Cited By ~ 53

Author(s):

M. F. Lyon ◽

T. R. King ◽

Y. Gondo ◽

J. M. Gardner ◽

Y. Nakatsu ◽

...

Keyword(s):

Molecular Analysis ◽

Pink Eyed Dilution ◽

P Locus

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Study of the ref(2)P locus of Drosophila melanogaster

MGG Molecular & General Genetics ◽

10.1007/bf00276934 ◽

1993 ◽

Vol 239 (3) ◽

pp. 361-370 ◽

Cited By ~ 11

Author(s):

Pierre Gay ◽

Didier Contamine

Keyword(s):

Drosophila Melanogaster ◽

P Locus

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Ac induces homologous recombination at the maize P locus.

Genetics ◽

10.1093/genetics/128.1.163 ◽

1991 ◽

Vol 128 (1) ◽

pp. 163-173 ◽

Cited By ~ 2

Author(s):

P Athma ◽

T Peterson

Keyword(s):

Homologous Recombination ◽

Transposable Element ◽

Direct Repeat ◽

Null Alleles ◽

Direct Repeats ◽

Ac Element ◽

Repeat Sequences ◽

P Gene ◽

In Trans ◽

P Locus

Abstract The maize P gene conditions red phlobaphene pigmentation to the pericarp and cob. Starting from two unstable P alleles which carry insertions of the transposable element Ac, we have derived 51 P null alleles; 47 of the 51 null alleles have a 17-kb deletion which removes the 4.5-kb Ac element and 12.5 kb of P sequences flanking both sides of Ac. The deletion endpoints lie within two 5.2-kb homologous direct repeats which flank the P gene. A P allele which contains the direct repeats, but does not have an Ac insertion between the direct repeats, shows very little sporophytic or gametophytic instability. The apparent frequency of sporophytic mutations was not increased when Ac was introduced in trans. Southern analysis of DNA prepared from the pericarp tissue demonstrates that the deletions can occur premeiotically, in the somatic cells during development of the pericarp. Evidence is presented that the deletions occurred by homologous recombination between the two direct repeats, and that the presence of an Ac element at the P locus is associated with the recombination/deletion. These results add another aspect to the spectrum of activities of Ac: the destabilization of flanking direct repeat sequences.

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